Who are the Howling Commandos? Well, they were an elite unite of commandos (that's obvious) led by Nick Fury. Oh, how the Nazis feared the wrath and guns of commandos such as the bowler-hatted "Dum Dum" Dugan, the lasso-wielding Private Robert "Rebel" Ralston, and the umbrella-smacking Private Percival "Pinky" Pinkerton. Made up of Americans, Germans, and Englishmen, they were something akin to the Inglourious Basterds of the Marvel Universe.
Kevin Feige says the individual Commandos (who probably won't be sporting their "Howling" moniker) "will be there as part of the larger Marvel Universe." I think this means you may see them making repeat cameos throughout Marvel movies, particularly since Feige made a point of confirming that one of them would be Private Gabriel Jones. Jones is one of Fury's best friends throughout the turbulent Marvel canon, so he may end up being Fury's right hand SHIELD man in The Avengers. It's a tiny piece of the Marvel Universe puzzle, but once you get enough of them, you'll have the whole picture. There, I've given you a poetic way to justify your Commandos excitement.