Hmm... well here is another idea on how to talk to an iphone wirelessly from a simple microprocessor device:
1. figure out how to
record voice , only from an application that just examines a small portion at a time.
2. hack a wireless headset so you can send different tones from your microprocessor to relay the information you want to send.
3. interpret the "voice" data to make sense out of it in your application
4. use pretty graphs/drawing api to wow people with your new fangled speedometer
