In most (maybe all?) casesYour factory radio does not support Bluetooth A2DP, You can get a bluetooth > aux adapter like one of these...
http://www.belkin.com/us/F4U037-Belkin/p/P-F4U037
or
I use this one in my '08 328i...
http://www.xtrememac.com/en-US/produ...harge-auto-bt/
or
http://www.scosche.com/motormouth-ii...-audio-car-kit
Can usually find the xtrememac one on sale someplace. I scored mine for $15.