Bonnie: Always go to the college camps where your son could actually see himself going, based on skill level, size, potential, academics, and cost. The academic test is to pick the school "as if" baseball didn/t matter. (I know its hard to do). Remember that most of these camps are just money makers for the assistant coaches.
As for skill camps, I wouldn't recommend them unless you knew a college coach would be there who would get a chance to work with your player. Although I am sure there are excellent professionals in your area who work with young players om a skill camp setting.
For showcases, there are none better than those put on by Perfect Game. Check their website for the one closest to you. But don't send him unless he is in top shape. He will get rated.
Hope this helps...