I just saw this on EngadgetMobile who saw it on eMercedesBenz who got it from the MB press release...just keeping it green by recycling folks.

Here’s how it works.  First, you must specify Optional convenience telephony (Order Code 386). The cradle then connects without any tools into the audio system either via the optionally available Media Interface or the retrofittable iPod Interface Kit.  Once the cradle is installed, your iPhone’s music and phone functions can be controlled with the help of the multifunction steering wheel controls, while the vehicle’s display is used to indicate the phone status, music functions, etc.  Other features include automatic recharging while your iPhone is attached to the cradle as well as increased reception with the help of your vehicle’s aerial.

If you’re interested, as already noted, the new Apple iPod cradle is available for ordering immediately (check with your dealer for local availability), while pricing is set at EU 249 (including VAT).

http://www.emercedesbenz.com