One of the cool things with OS X’s address book is that with my old Sony Ericson phone, I could manage calls. I would pair the phone with my Mac using address book (by pushing a little bluetooth icon). Whenever someone called, their vcard and picture would pop up on my screen and I could choose to answer or ignore it. Of course, I couldn’t talk through the Mac’s microphone/speakers, but it was nice when using headphones - I could still catch calls while the music was blasting. It’s also interesting to note that under the bluetooth utility, it states the iPhone supports no bluetooth services whatsoever - no file syncing or address book syncing. So, it’s really only for bluetooth headsets. That’s pretty lame!