Bluetooth, a wonderful creation. Are you sitting comfortably?
Bluetooth is a wireless technology created by Ericsson a good few years back to enable them to create what they called "personal networks". That means a network around your body. It works in the Medical and Industrial frequency band, about 2.1GHz I believe, but could be wrong, and as such is an unlicenced part of the frequency spectrum. The max. bandwidth available to one channel is around 720kB/s, but this is dependant on distance and power of the transmitting device. The personal network side comes from the need to have computers, communications and music type devices that you would normally connect using a cable of some description, and would get all tangled up. Bluetooth replaces this gubbins with the ability to have many devices using the same bit of bandwidth to talk to each other. The major applications it has at the moment are for connecting a mobile phone to a computer, and a wireless hands free kit to your mobile phone. There are such things as Bluetooth keyboards and mices in the pipe line, as well as MP3 players and the like. Its basically good for short distances (upto about 10 meters for a normal "client" device which uses a lowe power output, up to about 100 meters for "Wireless Access Points", such as for connecting your phone line at home to a wireless network. They have unlimited battery life as they are powered by the mains, and so can output bigger powers forever.
I have a Bluetooth headset which I use with my mobile phone, for when I'm in the car, and it works a treat. I intend, when I can justify it, to get a bluetooth PC card for my laptop so I can use both my ADSL connection at home anywhere in the house, and my mobile phone when I'm out and about. I currently have a good old fashioned bit of twisted pair running under the carpet at home to allow me to use the laptop on the internet else where in the house.
Hope this helps.