So my son is turning 4 next month.  He started using plastic clubs with real balls....well, that didn't last long before the clubs were broken.  He now has a set of the U.S.A. Kids clubs.  He's hitting the ball very well and is very interested in the game and cries when we have to leave the range.  My question is: When should he start taking formal lessons?  I know quite a bit about the game and am a descent player, but I can only teach him so much.

Thanks,

Ryan