yup.. this was added to Leopard 10.5... 10.5 is REALLY flaky though (all around, not bluetoothwise)... 10.5.2 is what you need.
but with 10.5.2 installed i use the Motorola MOTOROKR™ S9 with a Belkin USB bluetooth adapter (class 1 so get 300 ft range)... works really well... good for exercise 'cause they are light and they stay in your ears securely and can take sweat etc and they are sound isolating and have two sizes of in ear thingies for different sized ears.
plus have Advanced Audio Distribution Profile (A2DP) and Audio Video Remote Control Profile (AVRCP). AVRCP lets you control iTunes and volume from the head phones... back, forward, play, pause, volume up and down.. they are really cool and work perfectly.
http://direct.motorola.com/ens/s9/Headset_Home.asp