This is a contest entry for the "Keyboard vs. Mouse Speed Challenge", So please vote and rate. I hope you enjoy it!!
Step 1: Materials List
Ultra Bright LED Strip ( I used blue but white will work even better)
9v battery and clip
Step 2: Taking It Apart
Gut out the mouse by drilling any screws that require removing (usually one or two). Then take out the PCB and the battery holder. You'll find that if you have a double AA holder a 9 volt battery will fit right into it.
Step 3: Lights
Push the battery inside the the AA holder and connect a 9v battery clip to it and the attach to the LED strip. Remember some of these strips get very bight so do not look directly into them :). You can also drill a hole in the mouse to make room for a switch.
Step 4: Putting It Back Together
Now, push the strip through the area where the roller wheel for your finger was and drill the mouse back together