I have a Kennwood 642u. It is ipod direct, which will work with your iphone. I have the auxiliary cable coming out of the back of the radio and the wire runs into my glove box where I connect the wire and my iPod. I like it because it doesn't show I keep my iPod in the glove box, and I can control all of my iPod on the radio!
EDIT:
I'm pretty sure the stock radio doesn't have an auxiliary in the back to hook up, and I KNOW for sure it doesn't have one in the front, unless the radio changed from 2004- 2005 but
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