I'm kinda fuzzy on this too. I've heard the actors signed a three picture contract, but I'm not sure that means they'll actually complete three pictures. I think in many instances if there's a chance of a sequel they'll sign the cast to a few more pictures in case they shoot them. I believe they did that with Xmen and Batman with Christian Bale.
If they do make two more movies I'd like to know how they're going to fit into the grand scheme of things.
"Death, delicious strawberry flavored death!"