Original estimates were for publication in the first quarter of 2012. However, Sanderson as far as I know has not yet completed the book. He recently began work on the very final part, however. Yet that still leaves lots of proofing and editing to be done. If they give it a rush job it could still be out in the first part of 2012, but the last estimates I saw placed it in November of 2012. At a guess, it will depend on what the publisher wants to do, whether they want to cash in on it more quickly or give it a better polish. Either way, it'll be out sometime in 2012.