I saw the trailer earlier today. It appears to be a leak, but you could have fooled me. The only dead giveaway was that the link was dead due to "legal issues" when I checked it a minute ago when I checked (which is why it has been removed). I suspect this footage will be on and off You Tube until they either officially release the footage or release a shorter trailer.
It's an odd looking movie. It's like mixing footage of Clash of the Titans with footage from Iron Man. The costumes are incredibly cheesy and the establishing footage of Thor's home planet (?) excessively bobbles around. The last bit of the trailer is a strange scene.
I guess what I'm really trying to say is that after five minutes and fifty seconds of footage, I still don't have a good grasp of what this film is. All I know is that it reminds me of the live action Masters of the Universe movie.

I'm extremely interested to see the footage that was presented for Captain America and The Green Lantern.