Are you allowed to bring cameras into Comic Con?

I have a Nikon D3000 and I want to know if I can bring it onto the floor with me this weekend

Yes… I've never been to a con where cameras aren't allowed. For certain panels and such, they may ask you not to film/take pictures -- in which case it's in your best interest to listen (sometimes there are certain things that can never be played at a con again if someone posts it on youtube or whatever and you wouldn't want to be the person to prevent others from seeing it). And if you take pictures when clearly asked not to, you can be forced to leave sometimes.

If you're lucky enough to score a ticket, the answer is yes. Want proof? Here's 407, 000 pieces of evidence.