Two of the new Gyms will be Water and Poison. The unbuilt road between Nimbasa and Castelia through the desert seems to be finished. The new towns are south and southwest of Driftveil City. The entire eastern half of the region, the Pokemon League/Victory Road, and Iccirus City are all frozen over.

It also looks like the entire east side of Unova (halfway through the bridge) is frozen solid, that includes the starting town from BW1.
EDIT: Which SPD already pointed out and that makes me feel not special. Well, we'll get metagross at least.

Well I might as well post up the screenshots Serebii has as well what Serebii has posted:

(Click to enlarge)

1. Pokemon Black 2 and White 2 takes place 2 years (haha, very funny Pokemon Company ) after the events of Pokemon Black and White.
2. There are two new protagonists (pictured on the right page if for some reason you couldn't tell). This time they decided to stretch tradition and gave them sun visors. Your home town is a new location called Hiougi City (first time your actually from a city instead of a town).
3. The boy in the red shirt and spiky blue hair is the new rival. He looks smug so make a note to beat him time to time to put him back in his place.
4. Punk rocker girl with the Scolipede Guitar is Homika, a new Gym Leader who uses Poison-types. She's actually set to appear in the anime this June.

(Click to enlarge)

5. The Professor with the blue streak of hair circling around his head (?) is Akuroma who studies Pokemon Strength. Does this mean Professor Juniper won't be giving you your starter and he will instead?
6. Dark skinned swimmer guy with the blue twinkling hair is Shizui, a new Gym Leader who uses Water-types. He's most likely a Gym Leader of a new city called Hiougi City which has a Trainer School and a building with an underwater tunnel. Please ignored the cross out part, I read something wrong and will be making corrections in my next post...

(Click to enlarge)

7. Unova has been partially frozen (Kyurem be trolling, yo). It looks like the northern and eastern part has been encased in ice (this means Nuvema Town to Nacrene City, Mistralton City to Black City/White Forest). Also it looks like the land patch south to Driftveil City has opened up.
8. Pokedex extended to 300 and will include previous Generation species like the Riolu Family, Psyduck Family, Eevee Family, and Beldum Family (though they only show Metagross). Their Regional Dex numbers are Psyduck #026, Riolu #033, and Metagross #254 (none for Eevee though they show screenshot of you battling a wild one). Other previous generation Pokemon shown are Tyranitar, Mareep, Lapras, and Arcanine (and possibly two others but the picture is too small to tell).
9. Black Kyurem will know Freeze Shock and White Kyurem will know Ice Burn. If you're surprised about this please stick your head in a bucket of cold ice.

Okay, questions:
1. Two new Gym Leaders, so which Gym Leaders have been replaced? By the frozen area the following Gym Leaders are out of a city: Cilan/Cress/Chili, Lenora, Skyla, Brycen, Drayden & Iris.
2. What happened to other characters like Hilbert and Hilda (previous two playable characters, Professor Juniper, forementioned Gym Leaders, and Elite Four & Champion who cities/towns/Victory Road are now engulfed by ice?
3. Can the frozen parts of Unova be unfrozen and explored around, maybe post game?

EDIT: My next post will include more and better information (plus more personal thoughts) now that Bulbapedia has updated with it's more accurate info.

I'm hoping the previous two protagonists are somehow the new champions, though not sure how they'd do that since there are two of them. Unless they make it the decision based on the gender you choose or something.

Okay, with Bulbapedia having a more indepth information of what the translation says (and also chopped up the images), let me correct any information I got wrong and go into what I personally think (as if it matters...):

Changes Occurring In Unova:
1. Game is 2 years after events in the original Pokemon Black and White. Very cute, 2 years have gone by and the title of the games are Pokemon Black 2 and White 2 (and I guess the 2 can also be a reference to the who yin-yang concept and that there are two version sequels). In other words I have a feeling the number "2" is going to play a bit of a role in these games (like how there are 2 new Gym Leaders, though we'll get to them in a second). As for the games finally being confirmed to be sequels and them taking place a couple of years Black and White, I'm quite excited. As said many times before, not since the Gameboy era of games (Gen I and Gen II) has a Pokemon game been considered an actual sequel to a previous Pokemon game (at least for the main series). But this is the first time it's a full outright sequel instead of a the next generation of games which just so happens to have occurred after the previous generation like Gen II was to Gen I. However I'm not too sure how the 2 year gap will play in all this. Being this isn't a new generation, I doubt much is going to be changed (some construction being done in Black and White has been completed as you'll find out about, but that's merely a cosmetic change). I'm more of thinking along the lines of characters, especially the important NPCs. I guess I can see Drayden fully retiring and handing Gym responsibilities over to Iris, but that's the only one I can see. Maybe they might do something with Brycen and Alder, though I don't know. Though speaking of Alder, or more specifically the Championship, what are they going to do with that? I think it's safe to say that though the main character may defeat the Champion, they probably just receive a Championship title but that doesn't necessarily make them the Champion (though don't know how to explain how Blue became Champion in the Kanto games, maybe the previous Champion was looking to retire but it wasn't until Blue came along that anybody was able to defeat him and when Blue won he was able to retire finally finding a replacement. Kind of explains why though Red/Leaf beats him they don't become Champion and by the time of the Johto games Blue grew tired of being Champion or agreed to take control of the Viridian Gym letting Lance take the Champion spot (Red either turned down the position to train on Mt. Silver/they couldn't contact him while Leaf canonically doesn't exist). I guess what I'm trying to say is that I really don't see the Hilbert/Hilda being the Champion(s) in Black 2 and White 2, sure they won the Championship but does that really qualify them of being Champions? Though speaking of seeking the Championship, I wonder what will be happening with Cheren and Bianca? Oh so many questions and thoughts though I think I better move on.
2. Unova SEEMS to have been partially covered by ice. Bulbapedia has pointed out that the ice covering Unova doesn't look to be part of the map drawing but is rather on the picture itself to possibly cover-up any visible changes done to the other cities and routes. Because of this I'm not going to comment on this yet until we either get confirmation if the ice is part of the map or it's just a clever way of keeping too much from being revealed.
3. Of what we can see of the map, the following changes can be seen:
* New locations have appeared south of Driftveil City. The most southwest location is player's starting city: Hiougi City. Bulbapedia says it sees two new cities and at least one route, though I see three cities and two routes (unless they're counting the two furthest southwest cities connected by a route/road all be Hiougi City). Anyway glad they're doing something with that patch of land, of course now Unova is no longer a giant linear circle though I'm not complaining about that.
* As said, Hiougi City is the player's starting city and it has a Lookout Spot, Pokemon Center, and Trainer School. Oh good, we're going to get all the tutorial out of the way in one town. Joking aside, a couple of first time things are happening here. First, it's the first time the player is from a CITY instead of a TOWN. Second, it's the first time that the player's starting city has any interesting facilities besides from the Professor's lab. Though with all that said, according to the map, only your house and the "points of interest" make up the whole of Hiougi City (they don't show Pokemon Centers on the map, though if they don't include Pokemon Center I guess that means there could be other houses not shown like your rivals...). Also, if the new locations south of Driftveil City wasn't enough proof of them breaking the linearity then this should. Hm, I wonder if there will be a specific order of Gym Leaders like tradition or because the road splits they might let you choose which group of Gym Leaders you want to fight first. I mean them making you backtrack back and forth on a linear path seems a bit of a wasted opportunity. Also does this mean Clay might be the 1st/2nd Gym Leader this time around?

(click on the image to see the Corocoro page that shows what Hiougi City looks like in-game, including what the Lookout Spot has to show: an empty valley!)
* The road being built on Route 4 is completed and buildings have been built all along side it. So what does this mean for Desert Resort? I still see it on the map, though with the buildings built all along side the road there looks to be no way through. Also does this mean Route 4 is now a city? If it is, does that mean there is no more Route 4 or will they be pulling every route starting with Route 5 down a number?
* A new building has been added to the front of Nimbasa City, and a new area to the east of the Rondez-View Ferris Wheel. From what it looks like I think the building in front of Nimbasa City is just a bigger gate house (though they felt to add it to the map which usually doesn't show gate houses so maybe it does have a bigger role). Can't say much on the new area east of Rondez-View Ferris Wheel as there is a glare right in that spot so expect this post to be edited when clearer pictures come out.
* Driftveil City's lighthouse is gone, several craters have appeared in the city, and the construction zone and Cold Storage south of Driftveil are both gone. . Well the lighthouse never did anything except house a Water Stone. However the craters are a big mystery (underground cave-ins? The Gym was a underground mine, who knows how far it reached under Driftveil City). And being the new cities are south of Driftveil I've imagined that might have something to do with the disappearance of Cold Storage (what was the purpose of Cold Storage anyway?).
* Liberty Garden is now shown in the official artwork of the map, and appears to have been revamped. I'm assuming Victini isn't there anymore so they thought why not actually build something there (or make bigger).
* There is a section taken out of the side of the mountain in eastern Unova, and there are several buildings here. It's hard to see, best I can direct you is the spot above where the Poke Transfer Lab is. I think I see a plane meaning that maybe in order to access it you'll need to use the Mistralton City Airport (yes, I know it's actually a Cargo Service). But as for what is the building, I don't know.
* Challenger's Cave has disappeared. Nothing important was there so no loss.
* The webbing that initially blocks the entrance to Chargestone Cave is gone. Well duh, Clay destroyed it Black and White. Besides it was nothing more then an obstacle to keep you from advancing past Driftveil City until you beaten Clay.
* The Entralink's moat is now dry, and the inner area has changed. I'm more interested in what they're going to do about Black City and White Forest.
* There are several new facilities. One image shows a large glass tube going through water with Mantine swimming overhead. Sounds interesting, the water glass tube definitely sounds like something the new Water-type Gym Leader would have in his city.

(If you want to compare the two maps, just click on the images to make them larger. Left is Black and White map, right is Black 2 and White 2 map.)
4. Unova Regional Pokedex has been changed and now has 300 Pokemon in it.
* Known previous generation Pokemon included in the new Pokedex are Psyduck, Arcanine, Lapras, Eevee, Mareep, Tyranitar, Metagross, Buneary, Riolu, Lucario, and Weavile. I'm assuming this also means their evolutionary family members as well. Also so much for Unova only having new Pokemon in it's main game, though I suppose that promise only applies to Black and White which they did fulfill.
* Numbering has also been changed with known ones being Riolu #033, Psyduck #026, and Metagross #264. Possibility of having a Lucario and Metagross in your party for the main storyline? Awesome!

This post is getting kind of long so my next post will finish up with the new characters.

New Characters:
1. Black Kyurem's signature move is Freeze Shock and While Kyurem's signature move is Ice Burn. Anyone surprised? The answer is no. Though I'm curious on how Kyurem gains the move. Is it like how when Rotom changes forms it's given an option to forget a move to learn that form's special move? Is it possible for Kyurem to keep the move or maybe even have both (maybe for an event Kyurem)?
2. There are two new player characters. OMG THEY'RE WEARING SUN VISORS INSTEAD OF BASEBALL CAPS! Not since the days of Gen III's Brendan's wool-cap-which-everyone-mistook-for-his-hair has such a daring deviant been made! Anyway nothing really to say about our new protagonists. Some people have pointed out that they look younger then Hilbert and Hilda which I agree with however at the same time they still look older then the previous 4 generation player characters (if they were 10 and Hilbert and Hilda are assumed to be 15, I guess I would put these two at maybe, say, 12 (hey, if they're going to go with a "2" theme then I might as well TOO (get it, "too" sounds like "two"?)! ). Also does anyone think the girl's "dress" doesn't look quite right, like it's not really attached to anything and looks like it'll fall off any minute?

(Click to enlarge and see how much sillier Pokemon haircuts can get!)
3. Your rival is yet another childhood friend who is said to be passionate and "wages on a Pokemon's strength". Quote: "From now, I'm going to rage!" Rage all you like, you'll never beat me in a battle. I don't know what they mean by "wage on a Pokemon's strength". Do they mean he focuses on attacking instead of using status moves? The term "Pokemon strength" is going to be used later so I'm assuming this is going to also be a theme. Also, unless the player character you didn't pick will also be a rival of yours, could we be back to the old tradition of you picking one Pokemon, your rival picking the one that has a type advantage, and the other rots with the Professor like the older games?

(Let me correct myself, click to enlarge and NOW you'll see how silly Pokemon haircuts can get! )
4. A Pokemon Researcher named Akuroma who researches "Pokemon strength" and is doing something involving "latent abilities" of Pokemon. He's said to be mysterious and hard to read. I'm going to guess his full title is Doctor Akuroma (Professor named-after-a-tree in the English version) and he will be giving you and your rival your starter Pokemon. As I said with the rival, the phrase "Pokemon strength" is mentioned again so I'm assuming that's his research topic. Though at least here we also get the phrase "latent abilities" to go on. Hmm, "latent" means "present but not visible, apparent, or actualized". Could this be referring to Kyurem and its new formes? Maybe about "Hidden Abilities"? Or maybe how he got his hair to stay like that.

(Click to enlarge or not, his hair looks the most silly... no, ridiculous out of everyone. Seriously, with each character were they trying to out do the last character's hair style?)
5. Two new Gym Leaders:
* Homika, Poison-type Gym Leader. Her Gym is a "Live House" which is Japanese term for a music club where bands play. She's set to appear in the anime on June 14th. It's been awhile since we had a Poison-type specialist (last one was the Johto games which had Koga (Elite Four) and Janine (Gym Leader)... infact up till now being a Poison-type specialist seemed to have been owned by one family!). Anyway her design is interesting, essentially a punk (?) rocker with a Scolipede-based guitar. Though the question on my mind is what city does she belong too? Hmm, Poison-type, well many poisonous creatures live in deserts (and in the anime a large colony of Venipede live in the Desert Resort) and Route 4 looked to have just become a city so maybe there? However being she's a musician you could say she also fits in with Nimbasa City but if that's true what does that mean for Elesa?
* Shizui, Water-type Gym Leader. He's described as a big-hearted big brother who give passionate advice. Oh look, female fanservice. Wait, WATER-type? Um, Cress, I think you and your brothers might be in a bit of trouble... Anyway, judging by the screenshots I'm going to assume he's the Gym Leader of the new city which had been formed south of Drifveil City due to that city being spanned across the shore line. Also I'm going to assume that water glass tube place to also be in his city because, well, Water-type. Not to sure on his look though, tanned swimmer with a visible tan line? As I said, he's probably more meant for the girls to look at then the guys, though the sparkles in his hair and the blue zebra swim pants just makes him look odd to me.

(Click to enlarge, but don't expect any more silly hair... silly designs on the other hand...)

Is it wrong that i already have my team line-up planned out? @_@;

Guys. Guys. Guys. Guys. Guuuuuuys! The official site updated!

It revealed some new info. We get to see more of the Gyms.

Trainers now have animated sprites! All Trainers!

We have new villains!

To make it easier, here's it on Youtube. Anyway, time for trailer review:

0:36 - New villainous team? And no, I'm talking about the rival, I'm talking about the four people in black uniforms the rival is talking too.
0:51 - Pokemon movie making?... Are we replacing the Pokemon Musical with that?
1:07 - It's so nice of them to reveal the Water-type Gym's puzzle: We have jump and ride on lily pads to get across docks or push other lily pads to fill a missing section. If there are no Lotads anywhere I'm going to be a sad (not really, they'd still be appropriate though).
1:13 - Looks like they changes the HP bars.
1:15 - ANIMATED NORMAL TRAINER SPRITES! So now we have no more static sprites!

Pokemon musicals replaced with Sentai-esque movies? Oh my god this is the GREATEST GAME EVER.
The black-suited people kinda look like police to me, but idk.
The west of the region is filled with new areas, obviously to compensate for the frozen east, and i must say i like that.

Also, i know nobody cares, but i gotta post it somewhere so i have a reminder of the team: Snivy-Serperior [Murdock], Eevee-Espeon [Keima if male, Solana if female], Darumaka-Darmanitan [Raphael], Riolu-Lucario [Tenzin], Lapras [Mizore], Something that flies and Joltik-Galvantula [Caselli] (I'll likely get rid of Murdock for Caselli's spot)

@Edmasterchaos: No, don't ditch the Serperior, it can be really awesome. ;-; Kidding of course.

@Pikachu315111: Well, we don't know yet, so there can still be hope for Tepig!(Great line-up for Snivy, though :3)

As for my team, I was thinking about using Tepig since I have a Serperior in my Black cartridge, but now I want to use Snivy again since these games are sequels. As for my team, I'm planning on having Snivy again, and I'm interested in having one of the Eeveelutions on my team. Right now, I'm not so sure, I'll just have to wait until more Pokemon are revealed to be in the games.

As for Homika, 2nd Gym Leader, Zubat and Whirlipede, I'm calling it.

Serperior really can be awesome, and having it on my team worked a lot more than i expected it on my third BW playthrough, but still, i like other mons more.

As for Homika, Trubbish is a must. And she also has to be playing Trash Rock. Serviper and/or Arbok would also be good for her.