I happened on this at Frye's this weekened. Works great (I use GPS on my subnote Viao).. not cheap feeling at all. Paid $14.99.. the white one is PS2, the black one is USB (at Fryes that is). Much better than trying to reach for the touchpad or stick mouse. Substantially cheaper than the $100-200 wireless presentation mice most people use for CarPC stuff.

here's a pic/example.

http://store.yahoo.com/akidacomputer/4dscroltracf.html