Old Technology Seems to Work

After traveling with the unworkable FM transmitter, I thought I'd try old school. Vendors make a small cassette with a signal cable that comes out the end allowing an MP3 player (like the Zune HD) to be connected to play in the car. No transmitter, or static. Of course you need a cassette player in your car for this to work--which 2004 VW's do. If you have a noisy cassette player, it could be distracting, but it worked just fine for me.

The cassettes look like the following (courtesy of Google products):

This one is a Belkin and sells for about $15.