The APS maintains a website with tips, tricks, and plans for outreach activities.
Physics Central is a great place to read about physics in the news, learn about experiments and demonstrations, and connect students and the public to physicists.
The American Association of Physics Teachers has resources here.
A guide to physics on the web can be found at www.physics.org
The Institute of Physics has a resource page at http://www.iop.org/resources/index.html
The FYFD (fluid dynamics group) can be found here.
The Physics Instructional Resources Association website is very useful.
The Quarked!TM Adventures in the Subatomic Universe site is www.quarked.org.