I am currently using my iPod in my car via an Aux input adapter. I put my headunit on CD and then my iPod sound goes thru the car stereo. I control from the iPod, not the HU. If I get an iPhone, this should all work just the same for listening to music. Just plug into the iPhone's headphone jack. But what happens when a call comes in? If I click to answer the call I'm thinking that the caller's voice will be going into my car stereo. That could be cool. But what about my voice? Will the iPhone mic (on the bottom of the phone) pick up my voice? Or will the iPhone expect that I have the iPhone headphones in with that external mic?