American Association of College Registrars and Admissions Officers
American Educational Research Association
American Montessori Society
American Society for Engineering Education
Association for the Advancement of Computing in Education, AACE
Advisory Group on Computer Graphics (UK) Advising UK Higher Education on Computer Graphics,Visualization and Multimedia.
Association for Educational Communications and Technology, AECT
Association for Experiential Education
Association for Indiana Media Educators
Canadian Association of Law Teachers
Computers in Teaching Initiative, CTI (UK)
Educational Theatre Association
Institute of Continuing Legal Education
International Society for Technology in Education
National Council for Educational Technology (UK)
National Council of Teachers of Mathematics
National Education Association (USA)
National Science Teachers Association (US)
Some interesting sites include EdWeb Project, Educom, Globewide Network Academy, Online Educational Resources

You are also welcome to add on to this list by informing me of sites I have missed out.
Last updated 31st October 1996.