Hmmm..Blue tooth comes standard and I Phones will work just by using the USB cable that comes with the iPhone.. What you're looking for is this? (Extra bits)
(6NF) Music Interface for Smartphones, integration of iPhone 3, iPhone 3GS, iPhone 4 and iPhone 4S when using Genuine BMW Accessory snap in adaptor (playback of music via the in-car system and track names shown on the Control Display)
(6NK) Extended connectivity of Bluetooth/USB with Voice Control, incl. Bluetooth audio streaming, pairing of multiple Bluetooth devices, office functions and album cover display
The IPhone attachment cradel for BMW dont bother with it.. wont work with IPhone5 if you're thinking of changing.