Which radio do you have? If you have the Cassette w/ CD changer controls, Alpine makes a nice little unit and adaptor that we just put into my wifes Neon. We considered the mobil pro but the alpine was available locally and almost the same price. The name brand and local warranty service swayed me to spend the few bucks more. Places like circuit city or other warehouse electronics places probably stock it.
The hardest part is deciding where to put the changer (under pass seat?) and finding a nice out of the way place to run the cable. The Alpine has about 15 foot of cable, so you are only limited by space.
-Vic
99 SB QC 2WD 6SPD