Many interactive topics for Science for ages 7-11
http://www.bbc.co.uk/schools/scienceclips/ages/6_7/electricity.shtml
Chemistry for kids
Chemistry websites
http://chemistry.olivet.edu/chemistry_library.htm
Biology for kids
Biointeractives
http://www.hhmi.org/biointeractive/
Biology websites
http://shs.westport.k12.ct.us/mjvl/science/bioweb.htm
Cells: Animals, Plants and Bacteria
http://www.enchantedlearning.com/subjects/biology/cells/
Test your physics IQ
http://classroom.jc-schools.net/basic/sci-phys.html
Physics for 7-12
http://serendip.brynmawr.edu/local/IIT/projects/Glasser.html
Science online
http://www.dwmtech.com/Reference/Science%20references%20online.htm
Science links for everyone
http://www.msad40.org/mvhs/library/ScienceLinksMVHS.cfm
Lots and lots of ideas and links at Enchanted Learning
http://www.enchantedlearning.com/Home.html
Water in the City
Energy, including Zappa game
http://www.energykids.energyaustralia.com.au/
Cafe Scientifique is a forum for debating science issues
http://www.cafescientifique.org/
Discovery Channel - The big experiment
http://www.discoverychannel.co.uk/bigexperiment/home/index.shtml
Solar links
http://www.latrobe.edu.au/educationalstudies/solar/solar-links.htm
Science Museum
http://www.sciencemuseum.org.uk/about_us.aspx
Science websites for teachers
http://www1.curriculum.edu.au/science/
http://www.kn.pacbell.com/wired/fil/pages/listscilinksba.html