http://www.sciencenetlinks.com/tools.cfm?DocID=31&Grade=3-5
This is an interactive activity in which students classify various plants and animals, including organisms such as a frog, jellyfish, Venus flytrap, bat, human, and seaweed.
http://www.kidsplanet.org/
Learn all about wildlife through reading, games and experimentation.  Find out which animals are endangered and learn how to protect them
http://www.switchzoo.com/
Change the look of zoo animals. Make a biseephantig--the body of a bison, head of a cheetah, legs of an elephant and tail of a pig.
http://www.mrsbogucki.com/cgi-bin/quiz.pl?FILE=landform
This quiz asks students five questions about different landform
definitions.  They can check their answers and generate more quizzes. 
This could be useful for geography skill building and SOL prep.