Appalachian Air Canines AAC is a club based in York Pa (but has members from MD, NJ, PA) all over. The site has a lot of event information! These are great events for first-time competitors! http://aircanines.com/
K9Discussion A web forum for all that is K9 Disc--Some of the top competitors in the sport frequently post on this site. I HIGHLY recommend joining. They really are a wealth of information! http://k9disc.com/speak/
Quadruped Competitions Information on the Quadraped style competitions: strictly Distance/Accuracy (similar to toss fetch). Site about the rules, history, top teams. Great site! http://www.thequadruped.com/
SkyHoundz Skyhounz, a huge disc dog supporter and bringer of competitions. They have info on training, competitions, rules, equipment, etc. Great site for info! http://skyhoundz.com/
Southern Ohio Flying K9s This is a great club in Cinncinatti. They have been really helpful to me starting this group. They host a lot of fun events and even run a rescue. http://www.flyingk9s.com/