good sharing by W. K. Adams, Co-Director PhET Interactive Simulations University of Colorado, Boulder, USA
http://www.fisica.uniud.it/URDF/mptl14/dtlprogramme.htm
http://phet.colorado.edu/simulations/sims.php?sim=Faradays_Electromagnetic_Lab#topics

most popular hit
http://www.walter-fendt.de/ph14e/mfbar.htm


Gold mine find written by Wolfgang Christian, Francisco Esquembre, and Anne Cox
http://www.compadre.org/osp/document/ServeFile.cfm?ID=9414&DocID=1310#Doc1310