Ok, may not be of use to anyone but for a while now I've been looking for a way to have an aux in on my Pioneer DEH P77MP head unit. Pioneer say you need a CDRB-10 that plugs into your IP Bus input. Well anyway, they are about £75 BUT I bought THIS http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0324741629 (IP-BUS to RCA cable) for about £5 delivered. Got it today and it works perfectly with my iPhone 3g for ALL audio. (mp3/phone/satnav/etc..)
Cant see any reason to buy the official Pioneer converter, I dont think it does anything unless you have a CD changer as well.