You know, it would be nice to find out who those aliens warriors backing up Loki’s destructive rampage in "The Avengers" are ahead of time, assuming there’s an honest answer. Not because it’s essential to know or anything, but simply so it can stop the endless speculation and methodical scouring of clues and screenshots to figure out what’s going on. If nothing else, an answer would enable comic fans to stop chewing their fingers off in anticipation.
But this may be a real tip, and one that makes sense: a commenter at Slash Film points out that the aliens resemble inhabitants of the world Korbin, which is where recurring "Thor" character Beta Ray Bill is from. Beta Ray Bill is an alien who ends up getting a Norse hammer crafted for him, much in the style of Thor’s Mjolnir, and becomes a hero to his people. Given the previously established "Thor" connection, it’s not too much of a stretch to think that some of those people could be brought over into the movieverse to wreak some havoc.
It would probably be a little premature to introduce Bill to the Marvel movies -- for one, he looks like a horse, and we can look to the "Green Lantern" movie to see how well anthropomorphized animal aliens come off with the general populace (not well). Still, this would be a nifty little reference that wouldn’t require too much explanation or backstory, unlike the rumored Kree or Skrull inclusion. They’d just be some cool-looking aliens from a weird place, ones that Marvel fans would feel happy about recognizing and even happier that a more established mythos wasn’t being rewritten in the process (because we can’t say Skrull or Kree without thinking about where those worlds can go).
Of course, we’ll have to wait until "The Avengers" actually comes out to verify any kind of crowd sourced guess. Did you know that it’s out in barely a month, on May 4? It’s true!