You asked for it! Here's the technique I used for the glowing lightsabers in the Jedi Arena Rescue. I've got
Adobe Photoshop Version 5.0, you should be fine if your version is higher. Hereís a sample file to illustrate what I did.

1) Download the file that I've attached
2) Unzip the file lightsaber glow.psd
3) Open the file in Photoshop
4) Be sure you got History and Layers views shown, if not go to Window and click Show History, Show Layers
5) In Layers, find Background layer (this is the original picture), Layer 1 is Vader's lightsaber and Layer 2 is Luke's lightsaber.
6) To view the original picture, delete Layer 1 and Layer 2. Do not save! I just want you to see the original picture. Reset by clicking Open from the History box.
7) Click on Layer 1 from the Layers box, then right click to select the Effects box. You'll see the Outer Glow settings I used. Click on the selection arrow to view the Inner Glow settings I used.
8) Repeat the same step 7 for Layer 2.
9) That's all there is to it! You can tailor the color from the Screen mode to your liking and adjust the other settings for Intensity, Blur and Opacity. I suggest you practice on this file before doing it on your work.

For your own work, hereís what you do;
1) Open the pic in Photoshop
2) Create separate layers for each lightsaber color. This is the hardest part since you have to select each lightsaber from the pic. After youíve made the selections, copy and then paste to create a new layer with just the lightsabers.
3) Use the Effects from the Layers and select the Outer Glow option and change the settings as necessary. Select the Inner Glow option and change settings as necessary.
4) If you have overlays like in the sample file, be sure that the correct layer is on top (Lukeís lightsaber over Vaderís lightsaber).

Good luck!