http://phet.colorado.edu/new/simulations/index.php?cat=Top_Simulations
This web site from the University of Colorado has many different types of educational simulations for Physics classrooms. This web site also has links to mathematics educational simulations which is great, because I am a future mathematics teacher. It also has the newest simulations for math and science. I have gone through a few of them and the are something that I would use in a future mathematics class.