Rules of the game:
1) You are trying to get the stack of disks from the first pole to one of the others, in the same order.
2) You can only move one disk at a time.
3) A bigger disk can never be placed on a smaller one.
1) Use your mouse.
2) Click on a green pole to select the top-most disk in that pole for movement.
3) Next, click on the pole where you want to move the selected disk to.
4) To cancel disk selection, click on the same pole again.
5) Click on the new game button to start a new game.
6) The 0 disk game is a feature, not a bug. I thought it was funny.
Other pages for interested people:
Jim Loy's Tower of Hanoi page
Towers of Hanoi Adventure
J.P. Browns' Lego HanoiSolver
"Tower of Hanoi" by Gregory Weir (tangentially related)
Make your own non-virtual Towers of Hanoi at Instructables
Or just buy your set at Amazon