This happened to a friend of mine.
We plugged his iphone into my Belkin car adapter for ipods. It fried in less then 5 sec (didn't realize it put out 12v alla firewire, while the iphone doesn't like that)....
He took it to the apple store (said he plugged it into his laptop and this happened) and they saw the back all scratched and just turned him away, he was there less then 1min.
Call applecare and complain, I called for him and got some stoner in idaho, they overnighted a return box with a loner, no charge. Ge got his new iphone in a week.