For those of you interested in fabbing interior, body, structural or motor bay parts from composites like fiberglass, carbon fiber, kevlar, etc.
http://www.fiberglassforums.com/ more for interior parts.
http://www.racingcomposites.net/ for things aero- wings, air scoops, belly pans.
http://www.compositeforum.werksberg.com/ also on the aero side of things.
All sites have tutorials and technique discussions.