1. This shirtless guy could maybe be Captain America.
In a discussion with "Captain Awesome" from Chuck (Ryan McPartlin), Moviehole discovered that the actor has read for the part of the patriotic superhero. "Reading" for a part is basically just like getting an interview for a job, though, so McPartlin shouldn't start figuring out how to use his Captain America employee discount just yet.
2. Red Skull will be the villain.
You know that comic book character whose head is a red skull rather than a human head? Well, that's Red Skull, and he's going to be the guy Captain America fights.
3. The film takes place primarily around WWII.
Captain America will remain a member of THE GREATEST GENERATION. Director Joe Johnston said:
Virtually the entire story except the bookends are in World War II because we all recognize we have one chance to tell the origin story of how he became Captain America, you can't tell a modern story and then go back and tell the origin story.
So, presumably the film ends the same way the 1992 Mel Gibson film Forever Young begins.
4. The Invaders will have a large presence.
The superhero group whose members have included Namor, Union Jack, a Human Torch who looks exactly like the Fantastic Four Human Torch but is an android, and other little-known characters will dominate much of the latter half of the film, and there will be six of them. Good thing comic book movies aren't known for becoming clusterfucks of characters, or this could become a clusterfuck of characters!
5. Captain America has a really awesome shield.
Seriously, it's probably the best shield I can think of.
(Thanks to: Kevin, our greatest examiner of comics.)