I actually followed the trial a bit, since my mother and stepfather were seriously into it. Apparently, Travis (the kid) was leaving a store with some skittles and some Arizona Iced Tea. Zimmerman, seeing Travis, called the police from within his car and was told to remain in the vehicle, as authorities were on their way. Instead, Zimmerman left his vehicle and followed Travis. Now, personally, if I were a young African-American male (which I am) being followed by an adult Caucasian male who just left his vehicle, I'd feel threatened as well. What happened next is pretty much speculation, but it ended up with Travis being shot to death, and Zimmerman somewhat injured.
Even though I think the case was overhyped to death, I do think that Zimmerman was guilty. Clearly, he held some racist thoughts, even if not deeply. He killed a child, an African-American one at that, even when using a gun was not explicitly needed. Unless he is unhealthy as hell, he should have been able to handle a child of Travis' age through sheer physical force. Aside from that, the entire thing would have been avoided, had he remained in his vehicle. Because he chose to get out and follow someone, he put himself in a situation that was not in his favor. Long story short, I don't think Travis was exactly innocent, but I'm sure Zimmerman was, and still is, guilty.