head tracking for desktop virtual reality displays, developed by johnny chung lee, uses the wii remote to deliver 3D-like environments to the user, using a normal screen. experience it by watching the above video.
using the infrared camera in the wii remote and a head mounted sensor bar with two infrared led's, 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.
you can freely download his software and a tutorial, or go to his project's blog.