This is a quick video (slightly better quality than the last one, altho i do manage to get in the way of the camera a few times :-) of one of the apps that i wrote for Sandor at Corporate Design Cologne. It is a combination of multi-touch coverflow (sometimes with actual covers :-) and the light box app (which I have decided is basically like the hello-world of multi-touch apps, everyone needs to write one at least once :-)
Anyhow this is all running on my prototype table which is a diffused illumination setup, the tracker is BBTouch and it is all using TUIO to communicate. The tech is all core animation using CALayers. there is lots of mipmapping going on to keep the performance up even when there are tons of images, and it works quite nicely even on my macbook pro. BBtouch never tops 50% processor and xPrexxo is similar.