listening to the neofiles Singularitarianism episode # 018 where RU Sirius talks with Eliezer Yudkowsky, director of the Singularity Institute, about the singularity. Yudkowsky's description of the singularity is "the technological creation of smarter than human intelligence, and the resulting jump or discontinuity in human history" ... "it is a particular point in time when we have the first AI, or the first enhanced human that's smarter than anyone in the human race up until then". he mentions, Vernor Vinge, who first coined the term "singularity", "coined it by analogy with the singularity at the centre of a black hole where our model of the laws of physics breaks down - not that physics itself, necessarily breaks down, but our model of the laws of physics breaks down".
towards the end of the interview, Yudkowsky mentions some SF writers who have written about the singularity well : Vernor Vinge; (Australian!) Greg Egan and his books "Permutation City" and "Quarantine"; Walter Jon Williams and his book "Aristoi" about nanotechnology; and David Zindell and his book, "Neverness"