Some quotes from David Goyer:
"We don't know what we're going to call it yet — 'Superman vs. Batman,' 'Batman vs. Superman,' — but those two guys on screen, that's happening."
"To a certain extent, Superman, cinematically, hadn't been reinvented since the Donner films. We will be dealing with it in the coming film. He's not fully formed in [Man of Steel]. He will have to deal with the repercussions in the next film."