Companies like Innovative, Kegel, Jayhawk, Ebonite, and IBPSIA offer pro shop training classes.  If you could get your hands on one the class manuals that would be a good start.

Keep in mind, the actual drilling of holes in the ball is probably the easiest part of running a pro shop to learn.  As long a you have a grasp of how the jig moves in relation to pitch and can read a ruler, you could be putting holes in a ball in an hour.  Ball dynamics and fitting are a different story.  And dealing with some customers makes ball dynamics seem simple.