Just a month ago it was reported that 20th Century Fox registered the title Days of Future Past with the MPAA Tital Registration Bureau. We just weren't sure at the time if it would be a direct sequel to Mathew Vaughn's First Class.
We heard that X-Men: First Class would be the first film of a new trilogy. Simon Kinberg (X-Men: The Last Stand, X-Men: First Class) is currently writing the sequel with Vaughn and his longtime collaborator, Jane Goldman. Bryan Singer is attached to produce the movie, which is set to start shooting in January 2013.
The sequel is scheduled to be released on July 18th, 2014. It will be interesting to see how they tell this story. It makes me wonder if they are going to try and connect these prequel films to the original trilogy.
Here's the plot from the comic that the movie will be based on:
The storyline alternates between present day, in which the X-Men fight Mystique's Brotherhood of Evil Mutants, and a future timeline caused by the X-Men's failure to prevent the Brotherhood from assassinating Senator Robert Kelly. In this future universe, Sentinels rule the United States, and mutants live in internment camps. The present-day X-Men are forewarned of the possible future by a future version of their teammate Kitty Pryde, whose mind traveled back in time and possessed her younger self to warn the X-Men. She succeeds in her mission and returns to the future, but despite her success, the future timeline still exists as an alternative timeline rather than as the actual future.