With Mirror's Edge's PC release now set for mid-January we are getting more info on what type of rig you will need to run Digital Illusions' first person action game. The fan site On-Mirrors-Edge got some info on the system requirements for the game via DICE's Fredrik Thylander:

Operating System Microsoft Windows XP SP2/Vista
Processor Intel Pentium 4 3.0GHz or 100% compatible equivalent
Memory 1GB RAM
Video Card 256MB memory with Shader Model 3.0
HDD Space 8GB
DVD Drive 1x DVD Drive
Soundcard DirectX 9.0c compatibility
DirectX DirectX 9.0c
Network An online connection is required for access to Leaderboards

Of course, if you want all those cool Nvidia PhysX game physics effects that has been promoted for the PC version you have to have a compatible Nvidia video card as well.