The 3GS has a compass, so any applications that require a compass to work obviously will not work. The 3GS also has an auto-focus camera, and some applications require that to work (or at least work best with the auto-focus camera). Beyond that, however, there isn't too much difference. There is a speed boost with the 3GS, but in my opinion it's not as pronounced as some would suggest.
03-14-2010 06:39 PM