"MSA Remote is a remote control application for iPhone & iPod Touch that sends OSC messages over the wifi network. This allows you to control any OSC supporting applications such as Max/MSP/Jitter, PureData, Reaktor, VDMX, vvvv, Resolume, Quartz Composer etc."

and also
"You can see MSA Remote controlling a Java fluid simulation at vimeo.com/3975324"

I have nothing to add- these videos speak for themselves. Extremely impressed.