Marvel man Kevin Feige spoke from the set of "Iron Man," and he indicated that Cap will be the next movie to roll off the assembly line. They haven’t announced a director just yet, but they do have screenwriter David Self ("The Haunting," "Thirteen Days," "Road to Perdition") working on the project. The producer also mentions that the movie will probably be half modern-day and half period piece.
Also in the Marvel pipeline are: "Sub-Mariner," "Thor," "Punisher 2" (yes, still), "Wolverine," and "Magneto."
And yes, there already was a "Captain America" movie, but let’s not talk about it.
Source: Sci-Fi Wire