Optical mouse

I was looking at this http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1257038219 with the rotary wheel encoder to determine how far it moved. But what about an optical mouse? Are there any chance that they could be changed to work with the arduino too?

Older mice (PS/2 and serial, mainly) did use optical quadrature encoders, and yes, it is possible to remove them and reuse them.