Here is a good compilation of 100 tools for teaching and learning. The list was based on the results of  the votes of more than  50 learning professionals from 48 countries worldwide.

http://c4lpt.co.uk/top100tools/

The following collections should be useful for A/AS Level and a range of GCSE Physics topics.  In many cases you will require Java or Shockwave to be installed on your computer for the programs to run.

Java Applets on Physics

The Applet Collection

Fowler’s Physics Applets

Hyperphysics

Virtual Physics Laboratory

Maths,Physics and Engineering Applets