http://www.dictionary.com

(An online dictionary)
 

http://www.earthsky.com

(A useful site for those interested in astronomy etc.)
 

http://rabi.phys.virginia.edu/HTW/

(A How things things work site: the physics of everyday life)
 

http://ippex.pppl.gov/ippex/

(Internet Plasma Physics Education)
 

http://www-hpcc.astro.washington.edu/scied/physics.html

(PhysicsEd: Physics Education Resources)
 

http://www.cpepweb.org/

(Contemporary Physics Education Project)
 
 

http://www.physics.umd.edu/rgroups/ripe/perg/pergmem.html

(Physics Education Research Group)
 

http://www.rpi.edu/dept/phys/education.html

(Physics Education:  Resselaer Polytechnic Institute)
 

http://www.dmoz.org/Science/Physics/Education/

(Top: Science: Physics: Education)