Random results?
I started out with an iPhone 3G OS2 connected to my AVIC-F900BT via a Monster A/V iPod cable.
I routinely got the "This Accessory is not made to work with iPhone - Do you want to switch to Airplane mode?" error. I could answer No, and the phone would continue to work. The IPod would play through the AVIC, and I could make Blue Tooth calls and directory exchanges. It did not seem to charge, though on one long trip, it stayed at max charge for the whole trip, and was fully charged when I pulled it out of the car. Seems that charging works sometimes, but not others.
After some digging, I figured it was the Monster cable, so I found another cable on EBay that promised iPhone compatibility. This was a much cheaper cable than Apple's, Pioneer's, or Monster's, so I ordered it.
At the same time, I upgraded my 3G to OS3.
Now, I routinely get the AVIC error: "iPod connection failed. Please reconnect.", and on the iPhone: "This device is not supported by iPhone." Amazingly, if i take the AVIC's advice, and reconnect, it will eventually give me the Airplane Mode error, and stay connected. I can listen and watch videos on the iPhone. It may take 20 reconnections, but it will eventually work.
As an experiment, I tried swapping the iPhone for my 4GB Nano, and could not get it to connect at all - even after many many reconnections.
I then unplugged the USB connection from my A/V iPod cable, and plugged in the USB cable that came with the iPhone. Both the iPhone and Nano connected right up. I got no sound, I'm assuming because the A/V inputs were not connected to anything, and the AVIC expects all iPod audio from them - and not via the USB port.
It seems that there may be differences in cables, and possibly some SW version issues. I'm hoping future posters can clarify which cable, device, and versions they are using, and we can see if we can nail this down.
Looking forward to V3.0 of my AVIC-F series software for further testing.