PsychCentral provides an extensive list of online eating disorder support groups and forums.  

Bulimia.com is the location of the foremost publisher of eating disorder related books and materials, Gurze Books.  The site also contains a listing of online and offline support groups, treatment referrals, blogs by eating disorder professionals, articles, and recovery stories.  

Online Support, Groups, and Treatment Referrals

EDREFERRAL.com provides a comprehensive searchable database of treatment centers, therapists specializing in eating disorders, support and therapy groups led by professionals, free groups, workshops, online/phone counseling and courses, and research programs.