So the iPhone 3G failed to get A2DP out of the box, well apparently according to Gizmodo you can now get a A2DP adaptor to plug into the bottom of your iPod or iPhone and bingo you have A2DP. Known as the Bluetooth A2DP Stereo Audio Transmitter – INFINXX AP23 it is available to buy online now, full details after the break.

The Smallest, Silmmest & Lightest Design, You can "FREE" your iPhone NOW!
With this Tiny"About 5 grams" Adapter, You can enjoy Excellent High Quality Stereo Music from Both your iPhone 2G/3G, and iPod without the Trouble of Wire Anymore!! It should be the "Must Get" item for your iPhone and iPod.
Freedom from Wires Today!!

Features:

Add Bluetooth A2DP Function to your iPhone (2G/3G) & iPod series

The Smallest, Slimmest, Lightest A2DP Transmitter

Modern & Stylish Design: Perfert match with your iPhone (2G/3G) & iPod series

No Need for Charging & Batteries, Powered by the iPhone/iPod

Supports AVRCP function (Remote Control of Play/Stop, Forward / Backward, Volume Functions )

With LED Flashing patterns showing the BT connection status

Compatible with all A2DP Bluetooth Headphones / BT Speakers

** For the A2DP BT Headset user, you can pair your headset with iPhone (for Pick Up & Answer Phone Calls) & Enjoy Stereo Music through the Transmitter.

Support: iPhone (3G), iPhone (2G), iPod Touch, iPod nano(1st, 2nd, 3rd gen), iPod Classic, iPod Video, iPod (Color), iPod Mini.

Specifications:

Bluetooth Version: Version 2.0 compliant, Class II

Bluetooth Support profile: A2DP, AVRCP

RF Frequency: 2.4GHz / 79 Channel / AFH

Coverage Range: Bluetooth standard 33 feet (10 meters)

Power Supply: DC 3.3V

Package Content:

Bluetooth A2DP transmitter

User Manual

you can order online here but it looks like it is shipped from Hong Kong but they deliver worldwide