I have a 2000 Suburban with indash cd player and aux cassette. For $140, I installed a USA Spec PA11-GM45 interface unit that added Ipod and auxilliary unit capabilities (such as adding on a satellite radio). Total install took me about 40 minutes, and it was not difficult to install. The only things that did not come with the kit were an RCA y to mini stereo cable and plastic ties. This unit sounds great with the factory head unit, and even controls up to five (5) playlists on Ipods. There are other brands of these kits, so I am not advocating just this brand.
Hope this helps all other owners who are looking for an inexpensive stereo upgrade.
Hope this helps all other owners who are looking for an inexpensive stereo upgrade.