A PhD Student at CMU has created a VR Head Tracking system using a Wii remote and an IR sensor bar.  The effect is pretty cool!

Using the infrared camera in the Wii remote and a head mounted sensor bar (two IR LEDs), you can accurately track the location of your head and render view dependent images on the screen. This effectively transforms your display into a portal to a virtual environment. The display properly reacts to head and body movement as if it were a real window creating a realistic illusion of depth and space.

YouTube video link

He’s made the software available on his Wii projects site.

Wii gotta get one of these!