Last stereo I installed I was a senior in high school which was 1978 so not very familiar with aftermarket stuff since then. All I want is to be able to stream music from my iPhone or iPod. What do I change to add this feature? Just swap out the Sony head unit for one with Bluetooth? Current system is more than adequate for my needs as far as power and sound.

This is what I have currently all from 2003 I believe:
Sony CDX-CA810X AM/FM CD head unit
Kicker KX600.4 amp
Kicker speakers X 4
Sony 10 disc CD changer (will be removing this)

Thanks for any help!

Swap out head unit or if you have "AUX IN" RCA jacks on the back of your current head unit or use the "IN" ports from the CD changer your removing, buy a Fusion Bluetooth adapter for $40, simple install.

Ahhh that makes sense. I will give this adapter a try. Thanks