BBC News reports that Neil Gaiman has written an episode for the show, and its working title is The House of Nothing. Gaiman hasn't shared any details about his stab at the Doctor, but he did say the show will air in 2011 if everything comes to pass. From the writer himself:
And while I know it's cruel to make you wait for things, in about 14 months from now -- which is to say, not in the upcoming season but early in the one after that -- it's quite possible that I might have written an episode.
And if I had, it would originally have been called The House of Nothing. But it definitely isn't called that any more.
I can only begin to imagine what the writer will create for the new Doctor. Thoughts?