GOgroove SMARTmini BT ADVANCED Wireless In-Car Bluetooth FM Transmitter with Charging, Music Control and Hands-Free Calling for ANDROID, iPhone, Blackberry and Windows Smartphones
This product was easy to set up and reasonably inexpensive.  I had it use the FM transmitter, and testing with the car parked in my driveway it worked fine if I turned up the volume on both the device and my radio.  However, I have a noisy car and even with the device's volume set to the maximum value, the sound of the incoming call was too soft to be usable.  You can increase the volume on your radio, but the volume coming out of the speaker is a lot softer than playing an FM radio station.  I would have l