Proper fastpitch softball pitching motion

Question
I am a little league junior division (13 - 14) softball coach for Clintondale Fraser Little League in Michigan.  We are supposed to play by "high school" ASA rules but I am unclear on the proper pitching motion/delivery a girl must have.  I have seen other team's pitchers jump-glide forward releasing the ball with no foot touching the rubber and I have seen other team's pitchers have a foot touching when the ball is released.  Can you advise on the proper delivery.  Several of our division managers want one rule for all.

Answer
LL and High School pitching rules differ from ASA.

LL and High School do not require both feet to be in contact with the pitchers plate at the start of the pitch.  Only the pivot foot needs to be in contact with the pitchers plate at the start of the wind up.

There are no sanctioning organizations that require the pivot foot to be in contact with PP at the time of release for fast pitch.  The foot may drag away from the PP prior to the release of the pitch.  

As far as a desire to have one rule for all, you already do.  Contact your LL district commisioner to get a copy of the rule book.  LL fastpitch pitching rules are clearly defined in their rule book.