Florida Keys Schools
Sorry, I took a second look and realized that you wanted specific school info.
Offshore Sailing http://www.offshore-sailing.com/ is pretty well known. I don''t have any experiance with them, though.
I''ve done some sailing with a school called "Banana Sailing School". I''m not sure if they are around anymore.
You could try taking lessons before you go down there. I''ve found that it''s much cheaper in my area (VA) to take lessons and then go down and rent a boat.