Yep, yet another poor victim. Only happened to me when I updated last week with the new iTunes update and iPhone patch. The one that mentions fixing 3g/wifi/bluetooth issues. If you have the choice, don't do the update.
My Audi A3 (2007) Bluetooth worked fine and now, same symptoms as others, BT dropping out and even worse, the phone powers down, goes to sleep and locks itself to a black screen. Have to force a reset to reboot phone. Tried a total restore of phone through iTunes, no remedy. Apple support say you can't go backwards to the previous software. Seems that Audi will have to update or create a patch to catch up. Pain in the boot if you ask me.
Appointment next week with Genius Bar. If enough people do this, or even contact support, then maybe Apple will create a patch/fix....please!