The exact is unknown, But it will come out sometime in Spring 2011 For USA.
There is no English Version yet. It will come out late next year.
There is no black and white version.
There will be 649.
march 6th
The game will come out on June 2012...But it in JAPANESE GAME..and english version maybe come out on late of the year..
Fall 2012
Thundurus is exclusive to White version while Tornadus is exclusive to Black.
It has not yet been announced when Keldeo will be available for download in Pokemon Black Version and Pokemon White Version.
Black and White version 2 come out October 12 2012 In the UK and Europe.
Pokemon black and white 2 don't have a confirmed date yet but it has been confirmed that it will come out sometime in spring.
Fall 2012
I think it comes out in March 6, 2011