I found this on two of my favorite sites: The Force.net and HowStuffWorks.com
Howstuffworks “How Lightsabers Work”
Chances are that you have seen a lightsaber at one time or another, whether on the evening news or down at the local cantina. Therefore you know that a lightsaber is an amazing and versatile device that is able to cut through nearly anything in a matter of milliseconds.