You be the judge. Here is some of the Florida law that applies to the use of self-defense.

[X_Digger]

1. This may help..

http://law.onecle.com/florida/crimes/776.041.html
[div class='excerpt']776.041 Use of force by aggressor.

The justification described in the preceding sections of this chapter is not available to a person who:
(1) Is attempting to commit, committing, or escaping after the commission of, a forcible felony; or

(2) Initially provokes the use of force against himself or herself, unless:

(a) Such force is so great that the person reasonably believes that he or she is in imminent danger of death or great bodily harm and that he or she has exhausted every reasonable means to escape such danger other than the use of force which is likely to cause death or great bodily harm to the assailant; or

(b) In good faith, the person withdraws from physical contact with the assailant and indicates clearly to the assailant that he or she desires to withdraw and terminate the use of force, but the assailant continues or resumes the use of force.

The highlighted sections are the ones that I think will get Zimmerman a concrete cell.

eta: woops, hit submit too soon.

The first section- if Zimmerman was chasing / threatening / trying to detain Martin, he can't use this defense.

Re the second- If Martin took a swing at Zimmerman, it doesn't matter because Zimmerman was the aggressor.