Useful Links
EAA: Experimental Aircraft Association is the #1 source of books, information and fly-ins to learn about homebuilt aircraft!
Matronics: email lists for many different homebuilt aircraft. This is a vital resource for an aircraft builder as it puts you in touch with a worldwide community of many experts who have built the same aircraft you have, probably even more important that support from the manufacturer. I personally have got invaluable help from a builder in Brazil.
Aircraft Spruce: Great source of aircraft building materials
Kitfox LLC: Kitfox support and parts
Blue Sky Aviation: options for Kitfoxes
FAA: Your one stop for all legal requirements about homebuilt aircraft
AOPA: flying and aircraft ownership, one of the largest flying organizations.
Vans Aircraft: Largest manufacturer of kits by far. Very popular RV-6, RV-8, and RV-10 all metal aircraft
BRS ballistic parachutes: Whole aircraft parachutes
Landings: Hub of aviation information