I found this in Metacafe, maybe you can try it out to see if it’s work or not. It looks cool, you play the pong game with it so as viewing pictures and other stuff. Check out the requirements and the video after the break.

This is what you need for the project:
Multitouch Mini (MTmini) – a Cheap Multitouch Pad Website: MTmini discussion thread: Box -Piece of Clear Flat Sturdy Material (ie. Glass, acrylic, plexiglas) -Paper (ie. printer paper, tracing paper, almost any paper) -Webcam or Video Camera (tested on a Philips SPC900NC) -Computer (dual core recommended) -Optional Picture Frame Total Cost: $5 – $50 -Finger Tracking Software.