Ok, I have the Z1/2/3 with the CD-IB100II iPod interface unit. When I connect up my 3G iPhone I get the message "This accessory is not made to work with iPhone. blah blah blah..."
I have done some research and apparently Apple has disabled/removed the Firewire charging for this phone to save $'s (unsure if it is a software or hardware disablement). Many people are having issues with accessories that utilize the Firewire charging connections in their accessories.
I think I have a solution for this issue, and will be testing it out this evening. Basically, it will involve buying a automotive USB power adapter, then re-pinning the 30pin Apple connector in the Pioneer iPod interface (not sure if I can get away with just doing the internal plug, or will require re-pinning both the 30pin connector and the internal connection) and connecting the power connections from the iPod cable to the USB power adapter. I'd rather experiment on the $40 interface than the $300 phone!
I'll take lots of pics and post the results!!