My lecturer bought his Wii in last Wednesday, we set up the Head Tracking on his laptop.
Wasn't really that impressed, mostly due to the fact that Nintendo and the Wii's developers are too busy re-hashing old franchises and making tonnes of novelty crap, and this has a really high chance of never being used.
Also, I can't really think of many applications, a Time Crisis-esque game would be fun for about 20 minutes. (Which would be about 15 minutes longer that most Wii games I've rented) That and the fact another £50-100+ would have to be dished out for another controller/receiver and LED headset/glasses.