The guys from NerdKits have come up with a neat way to drive a small RC car using their iPhone. The video below goes through some of the details, if you have some similar ideas you can use their code as a starting point since they have made it available!

"Layering different simple systems together to perform one complex task is really at the heart of what engineering is all about. In this project we show how it is possible to utilize different technologies and piece them together to controll an inxpensive RC Car, with an iPhone. With the NerdKit serving as the bridge between the computer and the R/C Car, it is as an example of how useful microcontrollers can be when they serve as the glue that makes complex systems work together, and how with an understanding of microcontrollers a neat system like this one is achievable as a Do-It-Yourself weekend project. "

Thanks Humberto.