Bluebugging was discovered by German researcher Herfurt. His Bluebug program allow the user to take control of a victim's phone to call the user's phone. This means that the Bluebug user can simply listen to any conversation his victim is having in real life.
Initially, Bluebugging was carried out using laptops. With the advent of powerful PDAs and mobile devices, Bluebugging can now be carried out using these devices.
Further developments of Bluebugging tools has allowed Bluebugging to "take control" of the victim's phone. Not only can they make calls, they can send messages, essentially do anything the phone can do.
It should be noted that Bluebugging, like Bluesnarfing, is illegal in most countries.