I got hold of N Gamer magazine yesterday. The epicness that is the 3DS is due out in March 2011 for £180(pounds) I'm assuming that black and White will be released not too long after. If memory serves Platinum came out in April so that would be my best gusse.
If anyone wants to see the magazine I can bring it tomorrow to gamers world. Not much is in it about the Pokemon games that we didn't know, but there is a nice section 3DS and it's features.