yes it can be .... for xp it is a little tricky but for vista its very simple ... if both machines have vista then right click on the bluetooth icon next to the time and select 'Join a Personal Area Network' then it will search for the devices if the other machine has vista it will pick it up rather quickly and then u can connect
if u xp then see this link:
*www.conniq.com/Windows-networking/Bluetooth_PAN_xp-setup_03.htm