Come this “summer”, iPhone 3.0 — see our walkthrough — will allow iPhone users to enjoy new Bluetooth functionalityincluding stereo headsets, both the A2DP audio and ARCP control protocols. And if you're a developer, you likely have this functionality already for testing purposes.
A while back I took a preview look at the Motorola S9 Stereo Bluetooth Headset for iPhone 3.0. Looks like they've gone and grown up! If budget is less of a concern to you than sound, and you want to enjoy your audio on the go, the Motorola MOTOROKR S9-HD (the "-HD" being the key -- and really only -- differentiator here!) are something you definitely want to consider (available now from our sibling store at WMExperts).
Note: This pre-review will not be focusing on iPhone 3.0 functionality, which is currently in closed beta. It will concentrate only on the headset itself. However, for those developers needing an A2DP headset for testing 3.0, it’s our understanding this one works well on multiple units, over multiple carriers.