You can find my instructable on the Tron Legacy helmet here:
I initially purchased 30' of el wire from http://www.thatscoolwire.com with a 9 volt inverter box. This costume turned out to need a lot more wire then I had initially planned and ended up only being able to make the top half of the costume.
Step 1: Supplies List
El wire (I had about 29 feet left after the helmet)
Black long sleeve shirt
Blue painters tape
Fishing wire, preferably thin
Heat shrink tubing
Sewing needle (need to be able to fit the fishing wire through it)
"Helping Hands" (they help a lot when soldering the angle wire)
Wire (I used 20 gauge)
Step 2: Mapping the layout
My first step was to simply map out the location of the el wire on the shirt.
My second step, only when it came to the left chest side, was to map out the direction of the el wire. I did this by figuring out where exactly I would want each hole to be that let the el wire enter and exit the fabric. And where I would want the el wire under the shirt to be positioned.
The third step was deciding where to start the el wire and where to end it. I ended up deciding to go with two long pieces, one for each side of the design. Each length of el wire starts and stops at the bottoms of the arms.