Here is an update on the matter that is almost equally as vague:
http://www.gamezine.co.uk/news/games/a/alan-wake/remedy-answers-alan-wake-pc-concerns-$1309628.htm
Remedy answers Alan Wake PC concerns
Tuesday, 07 Jul 2009 13:03
Alan Wake
Remedy Games has attempted to answer concerns about Alan Wake on the PC, though their response is sure to fuel further speculation.
Yesterday we questioned whether Remedy's psychological action thriller Alan Wake would still be coming to PCs after a lengthy silence over this platform's connection to the game.
Now being published by Microsoft Games Studios, many PC gamers were unsure whether the company would hold back the PC release in order to bolster the Xbox 360's exclusive games offering.
Markus of Remedy Games has responded to concerned gamers on the official Alan Wake community forum:
"Hey all, I'm a PC gamer at heart (have a Core i7, Radeon 4890, 5.1 audio setup at home) so I do appreciate your concerns.
"Unfortunately all I can say at this point is that we're focusing all our efforts on the 360 version and will be making comments in regards to the PC at a later in time."
That doesn't sound too promising, with a timed exclusive period for the Xbox 360 version being very likely.