The expectation is that the first trailer for "Thor" will be in front of "Tron: Legacy" next week, but Marvel has already let the first teaser poster out of the bag.
The big question hovering over "Thor" has been how, exactly, they plan on selling the most bizzarely-premised superhero yet put to film (in brief: The Viking God of Thunder comes to Earth, takes up crimefighting, makes friends with Iron Man and Captain America) to a mainstream audience that generally hasn't heard of him. Whereas Hulk and Captain America are already familiar (or recognizable, at least) and Iron Man is fairly self-explanatory ("Oh, he's got armor. I get it."), Thor is Lee/Kirby nerd-weirdness personified: "Wouldn't it be awesome if creatures from Norse Mythology showed up here and now and started busting stuff up?" is an instant-win pitch... to the audience that's already going to see this. How do you get everyone else excited? The answer appears to be: gradually.
The start black background says "whatever this is, it's serious." The high-contrast black and white says "hey, weren't Sin City and 300 awesome!?" The eye-line direction from the head (beard, Jesus-hair) and armored-arm says "LOTR, Braveheart, Gladiator, 300 again" ending in the hammer that says "wait... he has a HAMMER? That's... new." And then the color-popped red cape says "Superman? Oh! It's a superhero... with armor and a hammer? So... Super-Gladiator?" The hope, one assumes, is for people to be mildly intrigued enough to go "Ooooh, that's what that was!" when they see the trailer not long afterwards.