Wireless PC lock $29.95 at Gadget Empire
This nifty little gadget retails for about $45 elsewhere
" * Effective range: around 2m
* When user is away, the computer automatically enters a 'Lock Mode' when the user is away from the computer by more than the effective range.
* Once the computer enters 'Lock Mode' and the transmitter / receiver pair is not available to unlock the computer, you need to enter a password to use the computer.
* One transmitter can be shared between several computers."