I believe Zimms will be acquitted.
The reality is that as far as anyone knows, he didn't pull his weapon until he was being physically assaulted.
Just because someone follows you does not give you an excuse to attack them. You are more than welcome to turn around and ask why they are doing so, but I don't think you can just hit them.
Truth be told, while I believe Zimmerman is a complete idiot and a moron and should not have followed Trayvon Martin under any circumstances, I do not believe you can convict him of murder.
Stalking maybe?
I don't know, but murder seems a stretch... And since that's what they charged him with, I expect he will, and should, be acquitted.
Just my opinion.