Depends on the program that you are looking for. There are several schools that are graded A+. Please visit he link provided to you beloved to view the Miami Dade school link to the list

Read Rick and Ines' answer, and while you're researching, beware of getting your trousers caught on a PALMETTO bush. They can tear. ;)

Clara - Fair Housing Laws prohibit Realtors from disclosing which are the "best schools" because it may be looked at as "steering". The dadecounty school website is a good way to do a bit of research with regards to the rating of a school. There are also plenty of private schools.
I recommend you start talking to people in different areas as well.

Best way to assist you with this question is to give you this link... to Dade County School System. There you will find all the answers you need.

http://www2.dadeschools.net/index.htm

Short Answer:
Your best bet is around the Palmetto High Area (Pinecrest, Saga Bay, Palmetto Bay, Cutler Bay, etc)

Longer Answer:
Well, do you mean Public or Private? High School, Middle, or Elementary?
They currently grade the public schools now so that you can see who gets the better grade.
However, the grading of schools is misleading. You could be in an A school, and have a poor teacher and be much better served going to a C school with a great teacher.
How are there great teachers be at low graded schools you ask? Because they get paid 20% more to teach at lower graded (Zone) schools.
My point is, the teacher is the key. But yes, an F school will not be as good as an A school, but some C,B, and A schools could really be almost the same should you get the good teachers which they all will have some good teachers.

As for areas, look to the rich areas. I can speak for the south part of Miami Dade and say that Palmetto and Coral Reef are the A high schools. The middle and elementary around the Palmetto High area are the best. Coral Reef is an A because it is a magnet school, NOT that its such a great area. It is an avg area.

Hope that helps.