rca input? dude your lucky if you have a %^*&*%ing out put back there. not even most after market head units have composite inputs unless theyre dvd playback compatible or what not or ipod ready. Your best bet is to buy a cheapy head unit and harness and wiring kit at your local walmart. make sure the new radio your buyin supports your needs (ipod ready) or auxilary in would even suffice for your needs. I saw one at walmart the other day for like 80 bucks that you could probably look into. There i just found your solution, a sony cd player with a 3.5mm aux input, just get a male to male 3.5mm cable from walmart for like 3 bucks, plug one end into your ipod and the other into the cd player and you can listen to all your podcasts through your factory speakers ;]