GSI Super Quality FM Transmitter/Modulator + Car Charger Kit - LCD Display, For Apple iPod Nano, Touch, Video, Classic - Cigarette Lighter Plug-In
The radio portion works well, but may require tuning to get a clear signal (Have used in 3 vehicles).  The only complaint is that it has caused some interference with one AM station when trying to use it as a charger; and this is only in an older vehicle that has a poor factory stereo in it.