Just received and setup the Blackberry bluetooth music gateway
http://www.amazon.com/BlackBerry-Rem...7692208&sr=8-1
and it's awesome! It paired with no effort, it sounds good - bass-rich, and loud - and it works whenever I step into the car with the phone.
It fits right in the iPhone case under the armrest, hooks-up via the aux-in and is powered by the usb port. So far, so good, and I saved about $950 on bluetooth & smartphone integration.