The Thor trailer that was once posted here is no more. Apparently the site housing the leaked video pulled it. I understand it's still out there on a few foreign web sites but I'll not post it here until official and authorized release hits the web.
For what it's worth, the trailer looked awesome. To paraphrase, Thor is thrown out of Asgard for being a punk. Odin dies but sends Thor's hammer to Earth. Anyone able to pull the hammer from the stone shall be the rightful heir to all England. Wait, no, that's not it. Whosoever pulls the Hammer from this crystalline mass shall wield the power of Thor.
In the mean time, Loki takes over Asgard and sends a Destroyer to kill Thor just in case Thor learns how not to be a brat and returns to take Odin's throne. Although not shown, I assume Odin comes back after Thor grows up.
Chris Hemsworth (Thor), Natalie Portman, and Anthony Hopkins (Odin) star in the adaptation of the Thor comic book from Marvel. I'm not much of a Thor fan but I can't wait to see this movie.