TouchOSC Bridge
I didn’t know this existed. Very nice!
"TouchOSC Bridge is a standalone tool application for Windows and Mac OS X that relays MIDI messages sent from TouchOSC to any MIDI capable application on your computer and vice versa. TouchOSC version 1.8 or higher is required to use this application."
Made by hexler (the makers of TouchOSC themselves)
TouchOSC is one of those must-have audio apps for iOS.