Hunger Games Movie

could someone give some clarification on the "Hunger Games" cast. Who has confirmed a role in the movie, what character they're playing. And if they haven't chosen yet, who the directors are considering of casting roles to and for what character?
I've been reading around and I really don't get what's going on, there are articles saying so and so has a confirmed the part of Katniss and then another article saying the same thing but a different person. It's confusing so could i just get some clarification on this subject.