Headfirst, referenced above, has an excellent reputation. In addition, some other camps/showcases discussed on other threads in the last few days are the TPX/Top96 academic showcases (www.top96.com) and camps at Yale and Princeton (the link for the Princeton camp is
http://www.princetonsportscamp...r_Camps/Baseball.htm ). Many of the same schools go to both the Yale and Princeton camps. DIII schools at the Princeton camp when my son was there included Haverford, Franklin & Marshall and Dickinson. The other schools there were top academic DI schools such as Princeton, Brown, Bucknell, Yale, Georgetowna and others. The Top 96 website will give you a list of schools that have attended each of their camps in the past...it will be a larger number than the Yale and Princeton camps, so you should go through and look to see who may be there that may fit your search.
My son attended the Princeton Advanced Baseball camp and the Top 96 Academic Showcase in Hartford. If you have any questions on these, I'd be happy to talk to you...just PM me.