According an interview with Captain America directer Joe Johnston at ComicBookMovie.com:
The scene between Chris Evans and Nick Fury was cut together from AVENGERS footage, so I had nothing to do with it other than agree to put it after the credits.
Even though the details are light, we learn a few things from this one brief statement.
1) There WILL BE a scene after the credits of Captain America: The First Avenger which continues the fine Marvel tradition. Don't be the guy that has to stop on the stairs to watch the scene because you weren't in the know.
2) The scene will contain some sort of exchange between Captain America and Nick Fury. At least I assume it will be the character played by Chris Evans that meets Nick Fury rather than Chris himself.
3) Just like the Thor post credits scene featuring Loki, Fury, and the Cosmic Cube, this scene will be directed by Avengers director Joss Whedon.
I guess I will stick around.