Expect A Dance with Dragons by October or November says Anne Groll, GRRM's editor at Comic-Con (reports Shawn Speakman is from Comic-Con on The Terry Brooks Forum):
George has indeed passed the 1000 page mark as of last week and those are, to him according to Anne, finished pages that will not be returned to. He also has several hundred more pages of not completed chapters that every week he makes progress on. Some of those will be in Dance; others will be in the next book. Anne also thinks she'll be getting the book by October or November, which to her would probably make it a February or March 2010 release, although the progress he is making is quickly happening and she could receive it sooner if those incomplete or mostly complete chapters come together faster.