I can't believe my favorite Pokemon game is getting a full blown sequel! Kinda amazing that I was actually thinking about something like this happening just days ago. It already has an expected June release for Japan, and an official US site is up. Also, this is apparently the second installment of a trilogy. Not only is this the first direct sequel to a Pokemon game, but if it truly does expand into a trilogy that would be a huge unexpected treatment for the series. Links below for more info.
U.S. Site: http://www.pokemon.com/us/pokemon-black-version-2-pokemon-white-version-2/
Japanese Site: http://www.pokemon.co.jp/ex/b2w2/
I have to say though, random sequels like this is kinda odd. What also seems weird is that it's for DS instead of the 3DS although I honestly prefer it on the DS. It would feel wrong not having them on the same platform. Plus, not many people would want to get a 3DS just for it. Also, i'm tired of the Pokemon fans complaining that it's not Pokemon Grey, RSE Reamkes, or Gen 6, there's nothing wrong with this.