Here’s a DIY LED how-to for computer cases. I like step by steps like this, they’re easy enough for anyone to do and build skills for more complicated mods. In this guide, you will learn how combine a spare molex connector and 2 LEDs to create a simple and effective lighting solution. Basic soldering skills are necessary, but apart from that, this mod requires very little experience (and very little money). Link.
DIY LED Lighting