The iFreq works pretty much the same as all the other FM devices for the Nano. Plug it in, pick a frequency, and hear your tunes through your fancy car speakers. The iFreq also charges your Nano and has a magnetic disc for you to mount on the dash.
Just try not to fiddle with your Nano too much while you're driving, putting on makeup, shaving, eating a McFlurry, talking to your Mom, and flipping an old lady the bird all at the same time. Oh yeah, we've been there.
Available 3Q 2006 for $79.95.