This is a tutorial to make a glowing effect behind the lines in photoshop.
The menus given are for photoshop CS 8, but i think it should be pretty consistent.

I origonally wanted to do this with an actual part of my comic, but the next bit Brit would be doing psychic wasn't for a little while so...

Once you add the feather, it should only show as a few dots around the lines. Don't worry about these, the actual lines will still be selected!

Brit © Me
Photoshop © Adobe