The way I did it was that I replaced my stock unit with the Alpine X01 unit. Also added in the Sirius Radio tuner. Bought myself an Apple Bluetooth Headset as well. The cable is routed into the glove compartment. When you connect it, you can fully browse all of your music visually with the LCD screen and dial. Podcasts work great as well and are separated from your music. Anytime someone calls, it pauses what you are listening to and you just answer your headset. The second you hangup on the person it resumes where you were. For me, it's the perfect solution.

You can also add an additional bluetooth box to the Alpine headunit for $99 more and they'll install a microphone in the car. Pretty much the same procedure as above, except that when there's an incoming call, it displays on the LCD screen who it is or the phone number of the person if they are not in your address book. Calls play through the speakers of the car. I've heard feedback though that the noise cancellation isn't up to snuff and if you go that route, people can hear their own echo on their end of the line.