Brian sent in this MIDI bridge for the iPhone, holy smokes this is cool and looks like it will get even better soon, he writes -

Istanbul based vj collective artificialeyes.tv announce the availability of i3L_v0.1, the first iphone to midi bridge for audio and video software as a free download. i3L (pronounced “i thrill”) is Freeware developed using Max/MSP as a support application for the native iphone application aka.remote by Masayuki Akamatsu. i3L receives pre-defined UDP messages from aka.remote.app running on the iPhone, scales the values to MIDI, and allows you to configure the sending MIDI channel and control change message number. i3L was developed to work seamlessly with our Real-time 3D VJ software Thrill, however i3L can be used with any audio or video software which receives midi messages.

i3L MIDI bridge for the iPhone – Link.