The latest GeekChicDaily newsletter dropped into my in-box a little while ago and one of their main stories is that Matt Smith has told VH-1 that the 2012-13 season will be his last before he ships off to Hollywood. The Doctor will regenerate just in time for the 50th anniversary. This is the link to the related video but I can't watch it here in the UK:
I heard about this a while ago (last year) BUT as there's a film being made (talked about) I had hoped it was just that..., meaning he'd be heading to Hollywood for the film BUT I haven't heard anything new since then so who knows really???