Well, no, Microsoft hasn't said anything about the status of Alan Wake PC. For all we know, they might have canceled it. In addition, when was the last time MS released a PC game? Gears of War, if I recall correctly. Still haven't seen anything suggesting that Halo 3, Gears of War 2, Fable 2 or any of the more recent MS games will ever come out on PC.
The only official word on Alan Wake is Spring 2010 Xbox 360 and Games for Windows according to wikipedia.
Playing: Wildermyth, Mass Effect Legendary, Returnal
Watching: Deadwood, Dune, Evil