iPhone does come with Bluetooth 2.0 EDR. This is the same standard found on most mobile phone these days. For those who doesn't know, in short BT 2.0 EDR allows you to transfer file between devices, sync data, send contacts, connect to headset and best of all listen music using A2DP bluetooth stereo headphones. The only problem is no one in this world except Steve Jobs knows what is in his mind to shut off the door on all BT stacks features limited to headset phone answering only. @#%& 
The good news is this provides accessories makers some cash making opportunity.
I found three devices that supports A2DP wireless stereo headphone/headset. All three allows feature small adapter that plug into iPhone dock. Supports the basic music control (play, rewind, forward, next, previous, volume) and answering call while listening to music.

The first is iCombi AP21. Priced at USD44. Read review.

The second Brando iPhone INFINXX. USD62. The smallest, slimmest and best looking (my opinion). Read review.


The final JayBird Bluetooth Stereo Headset + Bluetooth Adapter for iPod (2nd Generation). Bluetooth stereo headset included. USD159.99. Read review.
Since all are based on A2DP, the sound quality is very much similar and depends more on the bluetooth stereo headphones/headset. Since they are based on A2DP, iCombi and Brando claim to be compatible with all bluetooth stereo headphones/headset in the market, although not fully compatible in every features. As far as I concern JayBird Bluetooth Adapter only compatible with JayBird Bluetooth Stereo Headset. None of them support file transfer.
Here's the catch. All of them are pretty pricey. What if one day, Steve Jobs finally open up iPhone BT stack? What are you going to do with this investment? Ouch!
nice
nice product