if you go to Genki English you'll find a whole lot of useful lessons, exercises and games.
What I've found that's even more useful is the CDs they're selling off there. You can get a set of six CDs with exercises, worksheets and basically everything you'll ever need if you're teaching elementary, junior high or handicapped kids.
The cost is absolutely ludicrous (about Y24 000), especially for us Sefricans right now who're trying to recoup our losses from the first month. But what a group of friends and I are doing is pitching in together, buying the CDs and copying them between us. And I did not just say that. *Jedi mind trick* ;)
That way we all get the CDs, but we only spend about Y5000 each.