Well, just as Bungie confirmed co-op overseas, they finally confirmed it in the United States, and gives us a taste of what Co-Op will look like...by showing us the flavor of the co-operative characters.
Hit the link to view the details of it's exciting features...in English, and from Bungie.net.
Updates:
For those of you that don't follow the link, the two new playable characters that are present are two Sangheilis: N’tho ‘Sraom, and Usze ‘Taham. Unlike Halo 1 and Halo 2, each of the characters have different models...thus two Master Chiefs or two arbiters won't appear side-by-side being operated by gamers in co-operative mode.