We have more news in the form of a rumor today. It seems that a user on The Planet Forum talked with Superman: The Man of Steel co-writer Michael Dougherty while visiting the U.S. Capitol. Here's what he had to say about the upcoming sequel:
I asked him if he was a part of the sequel because everything I have seen says [Bryan] Singer and [Dan] Harris are writing the script and that he isn't mentioned. He confirmed that he is writing it with the two just like the last picture. I then expressed to him that I was hoping the delays of Superman: The Man of Steel weren't true. He said that they were on track and that the goal is still to have the movie out in the summer of 2009. He seemed a little hesitant about it but did his best to try and reassure that it will get done by then. I asked if he could give any more info on the film. He responded, "There are TWO villains," and he smiled.
Superman: The Man of Steel is scheduled for release in 2010.