ComPADRE is part of the National Digital Library concentrating on physics and physics teaching. http://compadre.org/

AGI's Educational Alliance Program provides eligible colleges, universities, military training institutions, high schools, and non-profit educational groups with free licensing of AGI products for instructional use. Educators can introduce a new dimension to the curriculum by giving students hands-on experience with the industry-leading, commercial off-the-shelf (COTS) software product used by tens of thousands of aerospace, defense, and intelligence professionals for national security and space initiatives. STK allows students and instructors to create dynamic, 3-D scenarios of complex space-related topics and solve real space analysis problems. http://www.agi.com/

Living Graphs - Homepage  for some neat physics and other science software. Free trial downloads available - Very reasonably priced. http://www.livinggraphs.com/enu/