In my opinion, the National Association for Gifted Children is the premier organization on everything gifted. The website is most beneficial for gifted education specialists & classroom teachers, but they also offer material & advice for parents of gifted children & school/district administrators.
I first found the NAGC website the year I became a gifted education specialist. They have wonderful magazines, brochures & pamphlets that make understanding gifted education easier for parents & teachers without experience with gifted students and their needs. Their website also has a book store with some of the best resources on gifted education out there today. I often use material from the NAGC through my company's work with gifted children & when teaching graduate courses on gifted education. Through my company I was fortunate enough to be able to attend last year's convention where I met Joseph Renzulli in person.
Over the years I've become more involved with the NAGC. I serve on the NAGC education committee as well as the newsletter editor for the Celebrate Creativity, the Creativity network's publication. As an education committee member I was able to moderate a webinar with Del Siegle from the Neag Center for Gifted Education/Talent Development. I feel that having a role in the NAGC gives me more of an inside view to all that is available to me from the organization.
Another organization that is often recommended is the Council for Exception Children, but I can tell you that having been a member, their focus is mostly on the other end of the special education spectrum with very little to offer on gifted students. If you are looking for resources for gifted ed, I wouldn't even bother joining the CEC.
The NAGC 58th Annual Convention will be held November 3 - 6, 2011 (this week) in New Orleans, LA. I'll be there, will you?
For more information about the NAGC visit http://www.nagc.org/ .