Marvel issued the following press release today:
Joss Whedon has signed an exclusive deal with Marvel Studios for film and television through the end of June 2015. As part of that deal, Whedon will write and direct Marvel's 'The Avengers 2' as well as help develop a new live action series for Marvel Television at ABC. He will also contribute creatively to the next phase of Marvel’s cinematic universe.
True Believers, rejoice!