PhysOrg Discussion Forum - Applied physics, nanotechnology, quantum physics, and semiconductor technology. Also discussions of the latest physics news. - http://forum.physorg.com/
Advanced Physics Forums - Intended primarily for physics majors, graduate students, postdocs and faculty. Get meeting information, theoretical and research information and exchange of ideas. Meant for the physics community throughout the world. - http://www.advancedphysics.org/
Scott Watson's Physics FAQs - A list of FAQs (Frequently Asked Questions) regarding Cosmology, String theory, Relativity and General Physics - http://www.het.brown.edu/people/watson/pages/resources.htm
Physics Forums - Bulletin boards on physics and related subjects. Includes related polls and a list of active threads. - http://www.physicsforums.com/