No, there's nothing official just yet: No casting calls or press releases ... yet. But we do know that author Richard Matheson recently sold the sequel rights over to the studio ... which means that someone at Warner Bros. is getting the ball rolling NOW. (And good for Richard Matheson, earning an easy paycheck like that!!) As Shock so accurately points out, this would make the first cinematic follow-up to the oft-lensed source material. (Neither The Last Man on Earth nor The Omega Man earned a sequel, which would make this the first.) Curious to see how they get Will Smith to "return" for the sequel. (Let me guess: It involves cloning.)
Oh, and if you liked the new movie version, cool. Do yourself a (big) favor and read the book now.