At the end of February, Fiat will be introducing three new European cars that will feature "Blue&Me" -- a Bluetooth system that uses Windows Mobile software to enable drivers to use mobile phones and other devices from controls the dashboard and steering wheel. This will include cell phone audio that is piped through the stereo system, a dashboard USB port for connecting music players to the stereo system, and a GPS navigation system. One other cool feature: if an engine light goes on, the driver can use this system to connect to Fiat about the problem and Fiat technicians can respond with a text message that displays on the dashboard.
I fully expect that in the near future the ability to connect cell phones to a car's audio system will be a standard feature on most new cars. Integrated GPS will probably follow closely behind.