This is probably everywhere by now, but I first saw it this morning on FBTB (it's other places, like the Brothers-Brick, as well). It looks like LEGO accidentally left pictures of an upcoming set, 10221, the Executor. Unless someone is pulling an elaborate late April Fools, this looks like a pretty awesome set.
BTW, I should note that the image no longer seems to be up on LEGO.com. I'm sure that any moment now, lawyers from LEGO are going to start contacting FBTB, the Brothers, etc, asking them to take down these images. Pretty much the same thing that happened with the Maersk train. What they need to understand is this - If I stand naked in front of my living room window, I can't really complain if people see me. If someone breaks into my locked house and sneaks into my bathroom to see me in the shower, well, for one they've got pretty sad lives, for two they are committing a crime. Posting any image on a publicly accessible webpage is the first case. Putting it behind password protection is the second case.