you can have it cheaper than a wii-remote and big tv!
all you need is a webcam, a basecap, some cheap electronics(1 battery, some cables, resistor, 3 ir led's) and a bit of soldering skills.
then you download this program and youre ready to go!
http://www.free-track.net/english/it works so that the webcam wich can see IR light tracks the 3 ir led sources mounted on your head and translates this in form of movement.
i use this when i fly around in ms flightsim x, or some driving simulation. its so great to use your head to look around in your cockpit.
its a great alternative for the expensive trackIR wich is above 150$... i endet up paying 10 € for the whole solution and my cheapo webcam does the job perfectly.
look here for an example video
http://www.youtube.com/watch?v=w2xfkcjPOIAok i admit its looking geeky, just make shure no one comes in the room when you wear your cap...

have fun!