I have an '01 Trac with the single-disc CD player, and I recently purchased the USA-Spec Ipod interface ($120) on www.crutchfield.com. I mounted the interface under the front passenger seat and ran the cable under the center console to the back of the factory radio. Then I drilled a hole in the side of my High-series console, ran the cord into that, and now that is where the Ipod lives.
The factory radio controls the ipod. Each playlist on the ipod is a separate "disc" on the "CD changer". It works out great once you figure it out.
It is a little more involved and expensive, but now I have Ipod quality sound (as opposed to those silly FM tuners or cassette adapters) and a hidden Ipod that probably won't be stolen out of my Trac - important in downtown Atlanta. Best alternative if you can swing it.