For twistedNERV, a friend of mine.
A'ight, here goes:
--You'll need to create three blank layers to do this.
1.Create a solid white line for the blade, width is your choice. Middle layer.
2.Copy its' layer, make this new layer invisible.
3.Move to the layer below. (Original blade layer.)
4.Add a blur that's just enough to notice from 100% distance.
5.Use the invisible layer to select the blade.
6.Move back to the original blade layer and grow the select substantially. Feather it at a high rate (I used 54).
7.Fill that with a low transparency, (14%?) repeat fill as needed. It shouldn't be all that eye-catching.
8.Use the invisible layer to select the blade.
9.Move up to the top layer and create a miniscule, blurred/feathered border (mine was 3px).
10.Fill this in with the color of your choice, again very lightly.
11.Use the invisible layer to select the blade. Then go to the bottom layer.
12.Grow the select substantially. Feather it at the high rate used earlier.
13.Fill this in lightly as well.
14.Now for the main color: Use the invisible layer to select the blade. Come down to the bottom layer again, but this time, only grow the select a small amount and feather a small amount.
15.This step will bring the color out of the blade. Keep clicking that fill at small transparency until you're satisfied.
16.Consolidate (merge) your four lightsabre layers.
17.BAM! There's your effect.
Feel free to tweak this for better results.