Lightsaber Photoshop CS2 Tutorial
First, open up the pic with you're lightsaber prop in it, for this tutorial, I'm going to use this picture of Qui-Gon Jinn and Obi-Wan Kenobi:
Make a New Layer (Layer > New > Layer) change the Mode from Normal to Screen, and check the box fill screen with neutral color black.
Take out you're polygonal lasso tool and wrap it around you're saber prop like so (turn on caps lock for more accuracy):
Then, Edit > Fill > White, once you fill it, hold CTRL+D to deselect.
Then Apply a Gaussian Blur (Filter > Blur > Gaussian Blue) of 1 pixel.
The duplicate that layer 3 times. And then on Layer 1 copy 2 apply a gaussian blur of 10, then on layer 1 copy 1 appy a gaussian blur of 20, and then on the origional Layer one, apply a gaussian blur of 40.
Then select Layer 1 copy 3 and press CTRL+E three times until you have just Layer 1 and the Background left in the layers palette.
Once you're there, goto, Image > Adjust > Color Balance and apply you're colors.
As a side note, I usually don't use the Shadow's area, I don't like the effect it gives the sabers, it doesn't really make them look realitic, but you can if you want to.
When you're done, you should have something that looks like this:
Hope this helped.