Science Grade Expectations -links to the Science Grade Expectations available in PDF, Word and RTF formats.  Expectations also available by grade cluster.
http://www.state.vt.us/educ/new/html/pgm_curriculum/science.html#ge

Science Lesson Plans and Resources- links to lesson plans and resources for all grade levels and all science areas typically taught in K-12 schools.
http://www.cloudnet.com/~edrbsass/edsci.htm

North American Mammals-a site from the National Museum of Natural History. Site contains a searchable database of all living North American mammals. 
http://web4.si.edu/mna/

DNA from the Beginning- an animated site which explains the basics of DNA, genes and heredity created by the DNA Learning Center. Image gallery, video interviews, problems, biographies, and links are included.
http://www.dnaftb.org

Using Live Insects in the Elementary Classroom- this site contains 20 lesson plans, information sheets, rearing sheets (obtaining, raising and caring for insects) and a bibliography.  Lessons are designed for introducing health topics in K-3.
http://insected.arl.arizona.edu/uli.htm

Amazing Space- uses the Hubble Space Telescope's discoveries to inspire and educate about the wonders of our universe.  Brand new Educators and Developers Section offers a wealth of curriculum tools such as fast facts, background information, and in-depth answers to common questions about astronomical topics.  
http://amazing-space.stsci.edu/

The New York Times Science Q & A- New questions posted daily and easy access to archives organized by topic.
http://www.nytimes.com/learning/students/scienceqa/

Science Bob.com- includes, experiments, links to web resources on many science topics, a teacher zone and more.
http://www.sciencebob.com/

Frogguts.com- the first true virtual online frog dissection. Requires FLASH 6 plugin.
http://www.froguts.com/

Animated clips found at Michael G. Shaikun's Animated GIF's website.