Using an FM modulation unit (designed for portable cassette/CD players) it should work fine. Obviously the sound won't be the best, but if you're just looking for the functionality this should do the trick. The one I purchased several years ago was just a tunable shortrange FM transmitter. Worked fairly well unless I happened to drive under a power line. They're quite susceptible to interference.
reason was asking cause i wanted run my laptop mp3s in winamp or a few other players with 3d sound plugins etc.. and visualization effects later on for screens in my vibe....