Bluetooth

Bluetooth is a personal area network technology that uses the 2.4GHz spectrum to provide a series of services. It is most commonly used in mobile phones and PDAs:

Taken from this excellent Overview

• Apfelwiki (put a fish in your ear)
• A balanced overview over at the Seattle Times
• The new SDIO card from Toshiba, endlessly rebranded for Palm and Pocket PCs:

• The Bluetooth filesystem (btfs) for Linux - a very neat approach to the problem of manipulating Bluetooth devices from the command-line
• HOWTO/Use a Bluetooth Headset - untested.