BMW announced the availability of Bluetooth for nearly all 2005 model BMWs, providing a new standard of convenience for in-car hands-free calling. Not all bluetooth phones are compatible but you could get a list of the compatible mobile phone from BMW

With a compatible Bluetooth cell phone drivers can place calls, answer calls and select numbers from the phonebook by simply using the multi-function steering wheel or dashboard controls.

Bluetooth equipped vehicles are shipped fully activated, requiring no further activation or installation. All that is required is a compatible Bluetooth phone. The owner must complete an initial pairing procedure in order to create a private wireless connection between phone and vehicle. This is only required once, all subsequent connections occur automatically. Up to four pairings may be held in memory.

Bluetooth is standard equipment on the 2005 5 and 6 Series models as well as the M3 Convertible and X5 4.8is. It is included in all other vehicles equipped with BMW Assist or a Premium Package. It is not offered on the 7 Series, which comes standard with a fully integrated portable cell phone. Some early production 2005 model 3 Series cars are not equipped with Bluetooth. Consult a BMW center for specific availability.

via phonemag