This video shows one of the vulnerabilities of some bluetooth headsets. To prevent this vulnerability, it’s best to invest a little more money into a more secure headset and making sure your headset is turned off when not in use. You can find all of the links and scripts used in this video, as well as find answers to questions you may have at the link below:
http://www.tinkernut.com/groups/videotutorial-extras/forum/topic/how-to-hack-bluetooth-headsets/