I'm thinking about selling my USA Spec iPod adapter.
http://www.usaspec.com/ipod.html It's very nice, but I might get the HD Radio replacement so I can listen to my stations in high definition... haha.
$100 shipped? I paid $120 for mine used on eBay when I bought it. It allows you to listen to your iPod through the CD changer interface. It also has an AUX input. You can browse via either the CD changer controls or the iPod.