It's nothing official from Activision. It's a movie made by a group We Can Pretend.
Don't get too excited about a Modern Warfare 3 announcement early next week. It sounds like the whole thing was a hoax. Joystiq recently heard back from an Activision representative who said, "There seems to be a great deal of speculation about the next Call of Duty project. Let me be clear that we are not revealing yet. Anything indicating otherwise is a hoax." GTTV Host Geoff Keighley also heard from an Activision spokesperson and posted a similar statement on his twitter account. Don’t worry, we’re sure Activision has Modern Warfare 3 in the works (and maybe Modern Warfare 4), but we’ll have to wait a bit longer for an official announcement.
Turns out that independent creative collective We Can Pretend is behind this stunt, and they're working on a project inspired by Call of Duty that is coming out on March 2nd.