My wife has a 2003 Trailblazer LS with factory CD headunit, no xm or bose. I found this Alpine DPR-RDS1 Ipod interface and am curious if any members have any experience with this, or thoughts about how it works. Its an FM modulator, the antenna is hooked to the unit, and the unit hooks to the antenna hookup on the headunit. Then you tune to an unused frequency to hear your Ipod (preset on the Alpine unit), instead of broadcasting the Ipod with an unused FM frequency for the antenna to pick up. (tried 1 of those and too much interference). I have been having a hard time finding something to use the Ipod with her factory stereo. If this is worth it, I may buy 1 for my 2006 2500HD with factory bose, no xm. Not interested in aftermarket headunits for either vehicle.

try these guys, i bought a USA SPEC PA15-GM, works awesome, easy to install
www.ipodcarpros.com (http://www.ipodcarpros.com)

Have you checked this out?

http://www.instructables.com/id/Adding-a-direct-line-in-to-your-car-stereo-for-an-/