Baseballmom, there are PLENTY of fields to practice on here in Tampa. Most are little league fields or Pony fields. You can try Forest Hills Pony Baseball or North Tampa Pony Baseball to name a few.
80Patriot is right on the money about The University of Tampa. They won the D-II World Series 2 of the past 4 years. Probably the top college baseball program in Hillsborough County.
I also would like to suggest going to the best high school baseball tournament in the state of Florida during spring break, The Saladino Tournament. There are 28 high schools in this tournament.
Dwight "DOC" Gooden, of Hillsborough High School, was the tournaments first Most Valuable Player. Since 1981 when it started, there have been 38 players that participated in the tournament and have gone on to play baseball in the Major Leagues. Twelve of these players were first round draft picks, and countless others have played baseball in the Minor Leagues and/or college. It's a great family event held at Brandon High School.
The tournaments homepage is:
saladinobaseballtournament.com