Well I finally caved in and bought an iPhone - and my favorite feature (and main reason for buying it) is of course the multi-touch capabilities. So currently OSCemote is my favourite app. Apart from having a few sliders and knobs which transmit OSC (similar to TouchOSC), it also has a multitouch pad which sends out TUIO messages, so any app which responds to TUIO (E.g. anything written with reactivision api) will respond. So I had to try out my visualization for the Roots project! Up and running in 5 minutes! Awesome! (I had to rotate the coordinates in my processing code though to have the long end of the iphone screen map to the long end of my desktop screen, slightly annoying that this isn't an option in the app... hopefully soon :P).

more info on Roots at memo.tv/projects/roots_minitek_festival_2008