Unfortunately, there are two major problems with the stereo Bluetooth (A2DP) support of iPhone OS 3.
1.) Many of you have already posted the previous/next remote controls not working. This, unfortunately, is a fundamental problem with the AVRCP implementation of OS3. Hope they’ll fix it in a next update.
2.) I’ve found a very hard-to-track and really annoying problem. A lot of (mostly older; that is, older than about two years) A2DP headphone models don’t work acceptably with the iPhone 3G while listening to / watching streamed contents (incl. YouTube) via Wi-Fi. (Local playback and cellular [GPRS etc.] streaming works.)
Please check out
A full compliance & test report of stereo Bluetooth sound (A2DP) in iPhone OS 3 for more info on this issue (particularly the last two updates; they are NOT in the original post but are posted later as separate posts at 06/24/2009 23.47 CET and 06/25/2009 13:47CET). The, in this respect, useless headphones also include the Plantronics Pulsar 590 (an, otherwise, excellent model).