There's an Alan Wake PC FAQ on the Alan Wake Community Forums dealing with the upcoming Windows edition of Remedy's third-person shooter/psychological thriller, saying its release on Steam is planned for February (thanks Joystiq). Word is there will be no Mac edition, nor will there be a demo. They answer other questions, and offer the following system requirements, subject to change:

OS: Windows Vista or Windows 7 (see below for Windows XP)
PROCESSOR: A dual core processor is required:

• AMD: Athlon X2 2.8GHz
• Intel: Core 2 Duo 2GHz

MEMORY: 2 GB
HARD DRIVE: 8 GB
VIDEO CARD: DirectX 10 compatible or later with 512MB RAM

• AMD: ATI Radeon 3650, 4450, 5550, 6450 or higher (per series)
• NVIDIA: GeForce 8600GT, 9500GT, GT120, GT430, GT520 (per series)

SOUND CARD: DirectX 9.0c compatible
INPUT: Mouse and keyboard, Xbox360 controller also supported

The goal is to get the game working fully on Windows XP SP2 and newer. There are still some minor (but technically challenging) issues we need to solve to get it to work 100%. We will announce official support after our testing has finished.