Just picked up a Griffin itrip today - this thing is awesome!

For those of you who don’t know, this is an FM transmitter that allows you to stream audio from your ipod to any nearby radio. Plug it into the ipod, play a song, and it displays an FM radio frequency on-screen (you can also select your own frequency). Then tune in on the radio - e.g. in the car, and voila, listen to your music without wires.

This is the best solution I have found to have essentially portable wireless speakers for an ipod, which is what I was looking for.