I took my daughter to the pond when she was learning curveball (or re-learning it, since she was originally taught to throw it like the men do, with the hand on top of the ball, and her new PC throws it like a girl, hand underneath).
Once they figure out how to throw sidearmed its an easier transition to throwing underhand rather then pushing. I want to see video!
Okay I found video! This guy has good form, it's more of a stepping style but I like his firm frontside and the fact he keeps his weight back with his nose behind his belly-button (I kid! But it's still useful)