Last year George R. R. Martin
made an announcement
about future plans for aSoIaF.
Initially the plan was to have five books, this later became expanded to six, with a five-year unnarrated gap between A Storm of Swords and A Dance with Dragons.
Martin now plans to tell the story of those five years in book 4 of the series, entitled A Feast for Crows, scheduled for release this summer. DwD is now book 5.
Two new PoVs are planned for the book: one has been confirmed as Cercei Lannister, but Martin is remaining tight-lipped about the other. There will, however, be no more Catelyn PoVs, and characters who are going through a "Learning Process" will only have one or two chapters.
Martin claims he can still finish the series in six books. Sources close to him, however, say that with the inclusion of FfC this is unlikely, and are betting on seven. If this ever increases to eight, then a diagnosis of creeping Jordanitis will be made.