You need a decent video card for a start.
I think my headset works at 30FPS, so your system need to be able to maintain 60FPS, to provide each eye with its image.
It works by darkening the lenses of the glasses alternaitng from one to the other eye, a bit faster then what you would notice flickering (24fps)
The screen alternates the image with each switch, each eye sees only the image intended for it then.
Sure its not perfect but when dialed in correctly is a MAJOR advantage in many games... not to mention how many winamp visuals are actualy 3D.
Down side is it doesnt work with LCD monitors, (allthough you now get 3D LCD monitors with their own glasses).