First thing first. You will need the ACM module from the dealer. I installed mine myself but I still had to return to the dealer to get it activated.

There is another thread from last week I think with more info.

 

The ACM works well actually. I bought mine on Ebay and tried to install it myself. After reading the above post I even tried to get the software and cable to program it but it was to complicated so I had it installed by the dealer also.
I thought i would be unhappy with the controlls beith on the iPhone but it actually works well because I don't have to go to the audio screen to change music. I can leave Nav or home screen on and just change the song on the iPhone.
I would be nice to have the display ..actually display the info on the iphone as well as the album artwork. but for utility the 08 ACM is fine. (09'-10' does control the iPhone/iPod - but still no album artwork )