Several popular science sites.

http://www3.imperial.ac.uk/media - Imperial College London.

http://www.galaxyzoo.org/

http://www.physorg.com/ - blog.

http://mathworld.wolfram.com/ -mathematics resources.

http://nobelprize.org/educational_games/physics/star_stories/game/index.html

http://www.ted.com - presentations.

http://spacetelescope.org/ - Hubble Space Telescope resources.

http://www.csiro.au/ - Commonwealth Scientific and Industrial Research Organisation,

http://webcast.berkeley.edu/

http://www.popsci.com/archives

http://www.newscientist.com/

http://www.sciencedaily.com/ - blog.

http://www.pnas.org/ - Proceedings of the National Academy of Sciences of the United States of America.

http://www.nature.com/

http://www.nasa.gov/

http://mitworld.mit.edu/ - presentations.

http://educhoices.org/articles/10_Universities_Offering_Free_Online_Technology_Courses.html

http://www.sciencemag.org/

http://www.gcarlson.com/ - illustrations and animations.