Qstarz has added MP3 capability through an FM transmitter to the new super-tiny BT-Q920. This is one tiny device, just 5.9 x 4.4 centimeters. It packs all of the power of a Bluetooth SiRF Star III chipset, with 20 channels, good cold and warm start times, and a high sensitivity.
We have a product page and not much else, actually. The real McCoy will be revealed in about a week or so, and we can report pricing for you then. Until that time, envision what it would be like to here your favorite tunes coming out of a Bluetooth receiver to your FM stereo.