I wish I had read this thread 1 week ago.
I bought a Pioneer DEH-P4150SD which is almost same with 4100UB except the missing IP-Bus connection and +SDCard option.
It has direct connection support over usb for both iPod and iPhone 3G but no bluetooth connection.
Charging iPhone3G over USB (iPhone OS 3.0) is working flawlessly but as mentioned above iPod application is locked while connecting over USB (deck control). It is not a big problem since I'm always listening manually created smart lists in shuffle mode.
All other features and applications are working normally (not locked)
My problem is that I can't receive ringtones or phonecalls over direct-USB connection. While I'm listening to music, when I get a call, sound fades out and phonespeakers itself starts ringing. But I want to hear the ringtone and also the phone call to be directed to car speakers. I don't expect BT-like contact lists control or dialing from deck options but this is silly not to hear sound when it comes to phonecall.
Do you have any idea? what should I do to direct phonecalls to in-car speakers. (I'm aware of the AUX option but I dont wont to use several connections and have a cable-mess around the dash)
Help appreciated, thanks in advance..