Um, I could be wrong here but I don't think that's him.

If you look at the page this Joe G is clearly talking to his "family and friends" that visit his myspace. Why would you set up a myspace with a fake name and then give the address to your family and friends?

What's the point of a fake name if everyone you know who goes on that myspace knows your real name?

Sounds like they couldn't find anything against Zimmerman so they searched myspace until they found someone they thought looked vaguely like him. Then, to get around the problem that, well, it's not George Zimmerman, they say it's his "secret" myspace page. And people eat it up.