I recently bought a Sony cdx-gt820ip for my boat. The "ip" suffix on sony head units indicates the iPod controlling functionality.
My buddy was over with his new iPhone. We plugged it into the head unit, sure enough; the head unit controls the iPod feature of the iphone.
(Side note: if you don't know what Pandora is, it's really cool. It's a custom tailored internet radio station that plays music based on statistical similarities in the music you like and specify
http://www.pandora.com The iPhone can stream music from Pandora)
Next we tried Pandora and the head unit kept taking control and resuming the iPod song that was playing. (grrr) Then I found that if I hit the Pause button on the head unit, it pauses the iPod song. This allowed us to connect to pandora via the iphone interface and stream music. I was impressed with the sound quality. deep bass and clear highs. Further, the iPhone should charge while plugged in.
Of course you could do this same thing with the Aux-in plugged into the iPhone headphone jack.
So now, I have to go buy an iPhone for Pandora.
Anyway - I thought other people would be interested in this 'undocumented' capability.
(Message edited by yosquire on July 31, 2008)