Bluetooth w/ GPS for a 2007 530xi

[Scrappe7]

Just got an 07 530xi with the premium sound package. I've figured out the basics of bluetooth and my iPhone 4 for phone calls but was wondering if there were any recommended GPS units that would work the same way. Ideally, the GPS would give directions over the car stereo. So as I'm listening to music, it would interrupt the radio to give turn by turn directions and then go back to the radio when done. Similar to the way it works for incoming phone calls. Anyone successful in doing this?

Also, is it possible to play music from my iPhone 4 over bluetooth through the car stereo?

Thanks