In April Mercedes-Benz will be launching the new Drive Kit Plus for the iPhone in the US market. It was introduced in Europe late last year in the A-Class. This system allows you to connect your iPhone to your Mercedes-Benz for a lot more than just phone calls and music!
This website has lots of details and demos about the features!
MSRP is expected to be under $1000 installed. Part numbers are not yet available.