There are tonnes of accessories coming out for the iPhone. The newest one is the smallest iPhone and iPod compatible bluetooth A2DP stereo audio transmitter. It only weighs about 5 grams, but this little baby packs a lot of power and enables you to enjoy superb quality stereo music your iPhone 2G/3G and iPod. It will be very hard to find a adapter as slim and as tiny as this one. It doesn't need the hassle of batteries, it can be powered by your iPhone or iPod. Also, it has LED lights that flash to show the status of the device.

This bluetooth A2DP stereo audio transmitter sets you back by $62. It is the slimmest answer to going wireless.