So I've decided that I wanted my own string jig, rather than borrowing the one at my local bow shop. I looked around at several examples of home made jigs and found one that was pretty straight forward, and does everything that I need. So for around $50 for materials and a few hours of my time, I built this. Not bad! Now I just need to go get some string, a serving tool and some serving and I can start making my own strings!
BTW it helps if you have a table saw and a drill press, but they're not required. I found the instructions for this jig on texasarchery.org
The pics aren't great, because I took them with my iPhone.