Link's to the Truth for Tots Series. Has tons of resources! Bible verses for small and older children, songs to sing, Veggie Tales to watch, activities to do. I'm super skeptical about most Biblical teaching ideas
A MUST do lesson LOVE, use small plastic bottles so each kid has one to keep. Object lesson on "Being in the world, but not of the world". We did this for home church and it was really cool. The kids got a lot out of it.