Charged rod & ball on string simulation (Physics Zone)
Electroscope activity (JavaLab)
a good Van der Graff simulation with heaps of different things to do
Animation of how circuits, current, voltage and resistance actually work
Ohm's Law (Phet)
Circuit Simulator (Phet)
Ohm's Law (FSU)
Crack the Circuit Game: work out the wiring if 18 different circuits
Bar magnets attracting & repelling (shape of field line diagram) FSU
Circular magnetic field around straight current-carrying wire (Fendt)
Bar magnet & compass (Phet) download and run java file
Electromagnet and compass (Phet) download and run java file
Compass inside an electromagnet (direction of magnetic field inside) (FSU)
Parallel wires with current attracting or repelling (MagLab)