I'm wishing I had subscribed to Gamespot like I had planned to - its a big download, clocking in at 1.3 gigs. Anyhow...

Minimum:
CPU: Intel Pentium 4 3GHz
RAM: 512MB (Windows XP), 1GB (Windows Vista)
VGA: GeForce 6600 with 256MB of VRAM (SM3 Required)
HDD: 8GB Free
OS: Windows XP
MONITOR: Resolution at least 640x480

Recommended:
CPU: Intel Core 2 Duo
RAM: 1GB (Windows XP), (2GB pre Windows Vista)
VGA: GeForce 8600 with 512MB of VRAM
HDD: 8GB Free
OS: Windows Vista
MONITOR: Resolution 1280x720

I'll let you guys know how it goes. My machine almost meets the recommended specs (got a GF 7900 GS instead of a GF 8600), and I've got a 360 pad on top of that. Nicely enough, it'll be $40 vs $60, won't complain.