Well being a big star wars fan, one of the first thing I tried in photoshop had to be the light saber, so I tried the simplest method I could think of then which i will be explaining to u below. There is another method that is NOT MINE, but was in the form of a tutorial on _www.ryan-w.com_, which I would be explaining as well. Before this lets keep some points in mind-
1) There are a gazillion more tutorials but none on instructables so here i am
2) I am discribing only the method to add the light saber effect in a picture, (videos are too cumbersome)
Step 1: GET UR PIC!!!!!
Simple get a pic of yourself or anyone holding a stick or a saber. (im using a random pic i found)
Step 2: START EDITING
-open pic in photoshop
Step 3: SABER MAGIC
First we take the line tool
-make sure the background colour(top right corner) is white
-set the width of the line at about 8 pixel(8 px)
Now take the line tool and starting from the base of your hand or top of your hilt stretch a line to the desired length. (this white line will be ur saber core)
Step 4: THE GLOW
for the glow goto
Playaround with the settings until you get the desired glow.
(i keep the setting at screen, with 100% opacity,0% noise and variable spread and size)
Step 5: VOILA - a LIGHTSABER
Just save and voila!