Trust me... I did weeks of research on this...

I searched for WEEKS to find one for my 2005 Honda Accord EX 6-Speed and I was able to find the best one at www.mp3yourcar.com. If you have XM, you will have to unplug it (as it uses your auxillery stereo port). I believe the product is called the Neo ION SP. It interfaces directly with your stereo, allows you to change MP3 tracks on your steering wheel controls or radio controls or iPod interface. (This was a big deal to me because I had 40gb of music and the only efficient way to browse it was through the iPod interface).

Oh, and the NEO ION SP is a better solution than the Soundgate SNHOND3 because the NEO connects to your iPod through the dock connection, which is superior because the audio output is line-leveled, while the SNHOND3 uses the output from the microphone jack. Also, another big benefit to me was that the NEO powers you iPod through the dock connection at the same time you are playing music.

FM modulation is out of the question for me. No point in using your iPod for near-CD quality music if you're pushing it through your FM radio. Plus if you're in a busy city, inteferance is rampant.