there was a guy over on the12volt.com forums that was trying to do this with an older gm radio.. i'm also playing around with the same idea for an older honda tape deck. basically, it's pretty complicated and takes a bit of know-how, as they aren't designed for this sort of thing from the factory (imagine that?)
i'm guessing it's stock since you said it's both cd and tape.. but even then that's odd since most chrysler decks are either or, not both. is it stock? what's the year make model of the car?