If your web browser supports JAVA, then you will be interested in
where there are JAVA-based physics simulations to be found. If your web browser does not support JAVA, you will find that some of the TIPTOP simulations are still kind to you. This example of 'graceful degradation' is really appreciated: you can look at still pictures and decide whether you want to acquire a JAVA system to look at movies.
PhysLINK is another service for physicists, and their page of links to computer software is
Dr. Reza Toossi has an interesting page of links to physics software
This author has produced a couple of pages which you may be interested in