Alice Eve, star of the comedy She's Out of My League is currently in negotiations with 20th Century Fox to play Emma Frost in the Matthew Vaughn directed film X-Men: First Class. It was rumored previously that Rosamund Pike may end up getting this role, but Pike is also rumored to take on the role of Moira McTaggert in the film. So she still may have an opportunity to be get in on the X-Men action.
Once the deal is finalized Eve will join James McAvoy as Professor X, Michael Fassbender as Magneto and Benjamin Walker as Beast, and as of right now Amber Heard is rumored to play Mystique.
Marvel has also confirmed something we already knew, and that is Tommy Lee Jones has been officially cast in Joe Jonston's Captain America: The First Avenger as Colonel Phillips. Awesome!