It is possible to control an aftermarket cdchanger with a computer/mp3-player. It would be rather neath, ha?
There have been a couple of threads abou this, but not much progress. Most have agreed that it is possible, but quite a lot of work, so you're really on your own so far. If you make any progress, though, or are looking for suggestions on where to start, let us know.
Well a regular car cd changer i really dont know about. Possible yes likely no...another solution cd rom changer...you can by a cd changer for your PC with an IDE or scsi connector...now that would be easily doable