So far they've announced there will be two new forms of Kyurem. They've also confirmed a new game will be announced.
Update:
Pokemon Black 2 and White 2 have been announced and are due for June in Japan. I am not sure on platform. Doesn't make much sense to be DS again to be honest. Kyurem has the following two forms. As you can tell, they seem to be a fusion of Kyurem with Reshiram and Zekrom.
Update 2: Nintendo DS, not 3DS, according to Masuda's Twitter.
Update 3: Better Image:
Update 4
Archaic on Bulbagarden just posted translations of Masuda's tweets throughout the day:
https://twitter.com/#!/NintendoUK/status/174072111235739648
Update 6: Nintendo of America has put out a press release announcing the release of the games in North America this fall as well.
http://www.nintendo.com/whatsnew/detail/QiS-9gZvsZyRMEDoXPC0MpsMqyMVKMnu
Update 7: Australia and New Zealand will be getting the game in the fall as well (sometime between September and November inclusive).
http://www.aussie-nintendo.com/news...te-version-2-heading-to-australia-this-spring
Box Art:
Update 8: Looks like the Global Battle Union is going to be overhauled:
Update 9: Kyruem's Formes retain Dragon/Ice typing
Sale listing on Amazon.co.jp reveals Typing/Height/Weight.
Black Kyurem Cover http://pokebeach.com/news/0312/3ds-white-kyurem-cover.jpg
Update 10:
Bulbanews has translated the information from the new Coro Coro issue. New storyline taking place 2 years after Black/White with new gym leaders. Most relevant to competitive players is this tidbit:
Update 11: Coro Coro May 2012
(copied from serebii)
First, it confirms Alder will appear early on within the game and asks the player to follow him
Cheren is a Normal-type Gym Leader while Bianca gives you your starter Pokémon as a favour for Juniper
Nobody seems to know where N has gone
New Professor is Professor Burnett who is in AR Searcher
Tornadus, Thundurus and Landorus original forms are Incarnation Forme. Their new forms are Sacred Beast Forme. They are 198, 199 and 200 in the Unova Dex and have no type changes
Tornadus' Sacred Beast Forme focuses on Defense, Speed & Special Defense. It is 1.4m and weighs 63.0kg
Thundurus' Sacred Beast Forme has increased Special Attack. It is 3.0m and weighs 61.0kg
Landorus' Sacred Beast Forme has increased Attack. It is 1.3m and weighs 68.0kg
Mecha Tyranitar is part of PokéWood. Icirrus City Gym Leader Brycen appears, has a confrontation with Homika's father who wants to be a movie star, and is part of PokéWood. PokéWood allows you to select a scenario and then make the movie. Various battles appear
Pokémon World Tournament allows you to battle many of the old Gym Leaders and Champions including those listed yesterday and Janine & Blaine. We're still in the process of translating so keep checking back
Update:
Pokemon Black 2 and White 2 have been announced and are due for June in Japan. I am not sure on platform. Doesn't make much sense to be DS again to be honest. Kyurem has the following two forms. As you can tell, they seem to be a fusion of Kyurem with Reshiram and Zekrom.

Update 2: Nintendo DS, not 3DS, according to Masuda's Twitter.
Update 3: Better Image:

Update 4
Archaic on Bulbagarden just posted translations of Masuda's tweets throughout the day:
Update 5: Nintendo UK Twitter account says Europe is getting the games this autumn!Translations of all Masuda's tweets on the subject this morning. Nothing new here, so we're not adding to the Bulbanews article.
https://twitter.com/#!/Junichi_Masuda/status/173534777398411264
Everyone, Pokémorning!!!! It's just about time for Pokémon Smash! To Start! Those of you who can't watch, keep an eye on these tweets!!! There will be an important announcement!!! (^^)/~~~
https://twitter.com/#!/Junichi_Masuda/status/173536168112168960
A universe first game announcement will be made!! Byt first, Pokémon Anime! Pokémon Library!! (girlish giggle)!
https://twitter.com/#!/Junichi_Masuda/status/173543044753272833
A universe first exhibition!!! Very soon, Game Freak's Masuda and a new Pokémon game announcement!!!
https://twitter.com/#!/Junichi_Masuda/status/173544047951093760
Hello!!!!! I will tweet!!![]()
https://twitter.com/#!/Junichi_Masuda/status/173548862294859776
The time has come for the announcement!!! (^^)/~~~
https://twitter.com/#!/Junichi_Masuda/status/173550148381716480
Pokémon Smash! After the announcement, important news will be posted on Twitter!!!
https://twitter.com/#!/Junichi_Masuda/status/173550186658926592
This June, the latest Pocket Monster work will make its apperance!!!! The title is "Pocket Monster Black 2 - White 2" for the Nintendo DS!
https://twitter.com/#!/Junichi_Masuda/status/173552394662195200
Everyone, please welcome "Pocket Monster Black 2 - White 2"!!! It looks like the official Pokémon website has just been updated. Legendary Pokémon are making their apperance. Please check it out!!!! pokemon.co.jp/ex/b2w2/
https://twitter.com/#!/Junichi_Masuda/status/173555282985758720
From the official account! RT @pok émon_cojp [Game]"Pocket Monster Black 2 - White 2" will be released simultaneously in June 2012. pokemon.co.jp/ex/b2w2/ #pokemonB2W2 #pokemon
https://twitter.com/#!/NintendoUK/status/174072111235739648
Update 6: Nintendo of America has put out a press release announcing the release of the games in North America this fall as well.
http://www.nintendo.com/whatsnew/detail/QiS-9gZvsZyRMEDoXPC0MpsMqyMVKMnu
Update 7: Australia and New Zealand will be getting the game in the fall as well (sometime between September and November inclusive).
http://www.aussie-nintendo.com/news...te-version-2-heading-to-australia-this-spring
Box Art:


Update 8: Looks like the Global Battle Union is going to be overhauled:
※The Pokémon Global Link will undergo a redesign to correspond with the Japanese release of Pokémon Black Version 2 and Pokémon White Version 2 in June of 2012. Due to the work involved in the renewal, the site will go offline temporarily. Season 5 will continue up until the site is brought offline. Further details about the schedule of the redesign will be announced on the Pokémon Global Link, as well as on the official Pokémon website.
Update 9: Kyruem's Formes retain Dragon/Ice typing
Sale listing on Amazon.co.jp reveals Typing/Height/Weight.
Black Kyurem Cover http://pokebeach.com/news/0312/3ds-white-kyurem-cover.jpg
Update 10:
Bulbanews has translated the information from the new Coro Coro issue. New storyline taking place 2 years after Black/White with new gym leaders. Most relevant to competitive players is this tidbit:
Check the link for the full run-down!The man in the lab coat is Akuroma. He is researching Pokémon strength. A cut-off portion of the photo mentions he is doing something regarding the latent abilities of Pokémon.
Update 11: Coro Coro May 2012




(copied from serebii)
First, it confirms Alder will appear early on within the game and asks the player to follow him
Cheren is a Normal-type Gym Leader while Bianca gives you your starter Pokémon as a favour for Juniper
Nobody seems to know where N has gone
New Professor is Professor Burnett who is in AR Searcher
Tornadus, Thundurus and Landorus original forms are Incarnation Forme. Their new forms are Sacred Beast Forme. They are 198, 199 and 200 in the Unova Dex and have no type changes
Tornadus' Sacred Beast Forme focuses on Defense, Speed & Special Defense. It is 1.4m and weighs 63.0kg
Thundurus' Sacred Beast Forme has increased Special Attack. It is 3.0m and weighs 61.0kg
Landorus' Sacred Beast Forme has increased Attack. It is 1.3m and weighs 68.0kg
Mecha Tyranitar is part of PokéWood. Icirrus City Gym Leader Brycen appears, has a confrontation with Homika's father who wants to be a movie star, and is part of PokéWood. PokéWood allows you to select a scenario and then make the movie. Various battles appear
Pokémon World Tournament allows you to battle many of the old Gym Leaders and Champions including those listed yesterday and Janine & Blaine. We're still in the process of translating so keep checking back