ENC The Eisenhower National Clearinghouse for Mathematics and Science Education is a K-12 math and science teacher center funded by the U.S. Department of Education.
Science Friday is a great resource for science teachers. This site covers all the latest topics and news in science from the NPR radio show.
Nova Science in the News From the Australian Academy of Science, this site covers areas from the environment to technology to physical sciences. Some interesting topics and perspectives.
Fun Science Gallery Instructions showing you how to build scientific equipments from relatively cheap materials. Projects include instructions for making telescopes, microscopes, batteries, sidereal indicators, and several other instruments. This site is designed to motivate children to engage in science.