[sdram]

Mesa college used an Android Optimus V phone with a sparkfun "IOIO" board and a custom app for their Robosub.

In terms of existing apps:
-Hackaday has had a couple posted I think
-http://www.robotsee.com/android.html

Mesa college is working on open sourcing their code but frankly for general purpose applications, the DIYDrones "PhoneDrone" or Google ADK community is where I would look. We had issues with the PWM outputs on the IOIO not pushing enough current for some of our needs, but otherwise the IOIO was nice to work with.

Lessons learned:
-magnetometer is no substitute for gyroscope
-relying on the cellphone's IMU limits your options or dictates cell phone selection(potentially driving up cost)
-having to use an external IMU detracts from some selling points of cell phone control
-RC Plane electronic speed controllers expect an arming sequence before they will respond to PWM signals
-iPhone vs. Android: Android has OpenCV...
Final Conclusion:
Make sure cell phone selected meets necessary specs required by application.