Check out these cool sites:

 

For Physics news and great links, go to PhysLink
The American Physical Society "Physics Internet resources" is here.
HyperPhysics is a very thorough "hyperlinked" site about Physics.
To find tons of cool interactive physics sites, go here. 
Physlets from the University of Oregon can be found here.
Astro-Web: Astronomy and Astrophysics on the Internet.
Johns Hopkins University's Virtual Engineering/Science Lab Course .