What is a cd changer? Is that like a betamax?
Just kidding, the factory radio has no provision for this, that means you have to use an fm transmitter or such.
Before you spend your money look into MP3 decks as I feel they are more convenient. You can get one that is IPOD compatible also.
It opens up more options and the prices really have come down in the past few years.
I have a pic in my gallery.