Pokemon Black and White 2 has just been announced on Pokemon Smash, an official Pokemon television program in Japan. The sequel to Pokemon Black and White will launch for the DS in Japan this June. No further specifics are yet available regarding North American availability, new Pokemon or any battle-system changes that may occur.
This will be the first numbered sequel to a traditional Pokemon game; previous generations have consisted of two initial releases followed by a single, similarly-titled "enhanced" version: Pokemon Diamond and Pearl followed byPokemon Platinum, for instance. Now, however, we'll have Pokemon Black 2 andPokemon White 2. Whether this distinction is purely cosmetic or carries heavier gameplay implications, remains unclear. All we know for certain is that, by now, the PokeRap must be several hours long.
Update: A statement on the US Pokemon site calls the games "Pokemon Black Version 2" and "Pokemon White Version 2" and says that details will be sent out "throughout the year." Looks like the game is heading to the US as well -- surprise!