I tried a few FM Transmitter over the years and have had absolutely no luck. My previous attempt included an early version of the Griffin Road Trip although it's worked for others it did not work for me.

My latest attempt was a pleasant surprise "Kensington Liquid Deluxe for Ipod'. This is not CD quality, as we all know, but I found the sound quality quite accepatble. This unit will also charge your Ipod. Also displays the song title on the Crossfire radio. Also automatic search for best channel. There is a long cable to the Ipod and you need to move the cable around for the best reception. Original List Price was $99 and with a street price as low as $20. I paid $30,

Customer reviews are pretty bad. My experience was great and if the reviews were good the street price would not be discounted so much. By far clearest sound I've found. I just don't want to replce the radio head unit and I would miss the Navigation Unit (even though it sucks).

http://www.pocket-lint.com/reviews/review.phtml/2766/3790/kensington-liquidfm-deluxe-for-ipod.phtml