Rupert Wyatt, director of The Escapist, will be directing from a screenplay written by producers Amanda Silver and Rick Jaffa. As for what it's about: "RISE OF THE APES (tentative title) is an origin story in the truest sense of the term. Set in present day San Francisco, the film is a reality-based cautionary tale, a science fiction/science fact blend, where man's own experiments with genetic engineering lead to the development of intelligence in apes and the onset of a war for supremacy."
That actually sounds not too unfamiliar from the premise behind Michael Crichton's novel Next, except his scientists' genetic experiments lead to a corporate war for supremacy, not an actual, kill-all-humans war for supremacy. As for who will be playing those scientists...well, we'll just have to wait and see; Fox hasn't announced any casting yet. They have, however, announced that the ape half of their cast will be completely CGI. You can blame Avatar for that one.