Big Red ‘L’, have got bluetooth on Ericsson phone, but it’s a common spec to Nokia, Ericsson, Sony, 3Com and lots of others
Bottom line it’s a radio data link between various electronics devices.
Two most common uses that I make of it is
1/ Link between phone, and full hands free car kit. No plugging any more, it just "talks" to the hands free kit, understand the latest generation of Saab cars come with built in bluetooth (those clever Swedes!), useful for jumping in and out of the car.
2/ Datalink to Sony notebook (built in bluetooth, but you can buy a PC card for other flavours), so car surf from any ware using mobile phone and notebook, notebook talks to phone on bluetooth, and phone talks to internet. Basically, you end up with two radio hops, notebook to phone, then phone to internet
Haven’t invested in the bluetooth fridge yet, reckon that contents of the fridge are more important!