I bought a DVD talking about Electric Guitar setup and maintenance. The DVD is titled Fret MD: Electric Guitar and Bass Setup and Maintenance with Al Markasky.
Short of a class on this subject, I thought the presentation of the areas covered were excellent. He covers the main areas of setup which in his process is 5 steps. Some of the steps still look a little scary but that is probably more about changing the current physical setup when you are not an expert.
He also covered a couple of small things regarding maintenance.
The complete process of setup and maintenance would be really useful on a beat up garage sale find. Taking the steps here and maybe adding a few like part replacement (he only covers nut replacement but if he covered changing out electronics, that would be very useful) could turn a non-functional garage sale find into a great instrument.
Overall, this is a good DVD and could be great if it included electronic replacments.