Here’s another app due to hit the app store at some point. Here’s what the developer’s site says.
TiltSinth uses the iPhone’s accellerometer to make some squeals in a simple synth patch.
The info page (hit the (i) button) shows three sliders that control the central frequency, the accelerometer slew rate and the amplitude. You can also change the OSC server host:port configurations. You can change the OSC id so you can run several iPhone TiltSynths simultaneously into an OSC consuming patch. The control rate is roughly 50 cps.