Glen's L3phy youtube channel (nuclear ideas explained in 11 vids)
PHET (likely the best one! but it needs to download and use java)
simplistic animation that works with Ek(max) = hf - work function idea (for outer-shell (valence) electrons only)
Binding Energy Idea (download the swf file)
Binding Energy per Nucleon graph (download the swf file)