It turns out hang gliding is actually very well organized. The USA Hang Gliding and Paragliding Association has tons of information on their site, including listings of clubs, instructors, and competitions! There are also a lot of articles about everything from safety to certification. You can learn all about thermals and speed. When you're ready to commit, you can read the one about how to buy a used hang glider. This is the place I would start if I ever were to take up the sport, but don't hold your breath!