I just stumbled across a free midi controller app in the iTunes app store. The short of it is it turns your iPhone/iPod touch into a ~one octave midi controller, but you can change octaves with the touch of a button. I loaded it up just to check it out, (you have to download iTouch Midi OSX, also free) and it does work. For us VDL users the octave changing can get tiresome, plus there's no visual indication to show what octave you're in. I'm sure it's great for some uses, but it seems it may be more of a novelty for most of us.
Still pretty neat though. For anyone needing something smaller than Oxygen 8. Here you go.