As gizmodo says: "You are looking at Apple's next iPhone. It was found lost in a bar in Redwood City, camouflaged to look like an iPhone 3GS. We got it. We disassembled it. It's the real thing, and here are all the details."
Also there is a mail published by gizmodo. That seems to be real and I think Apple will announce this new iPhone in recent days. The other possibility is that Apple may use the power of word of mouth.