Normally I am pretty skeptical of plans and guides for solar projects offered for sale over the internet. Most of them are scams. But, George's plans for the Tracking Parabolic Collector are an exception.
George has done a great job on these plans. They are very detailed, clearly written, and provide good photos and illustrations for every step. Full size templates for the key parts are also included. It can often be frustrating to find parts and materials for internet projects -- to make this easier, George has stuck to commonly available parts and materials, and lists sources (often multiple sources) for all of the parts and materials. He has also included a lot of the design logic that lead to the final design -- this can be quite helpful if you are considering a variation on George's design.
The other thing that you get with the plans is George himself to answer questions and consult with. I've exchanged a number of emails with George, and I've no doubt that he will come through on this promise.
George sent me a draft copy of the plans, and I've read them cover to cover -- I can recommend them without hesitation. If you are seriously thinking about building a concentrating solar collector, I'd say that its worth getting these plans as a reference even if you don't plan on building exactly the same setup as George did.
This page gives some of the details and sample pages: http://www.ffwdm.com/solar/solar-index.htm
Gary March 28, 2010