Stross has a good Singularity novel, Accelerando.
Vinge has an interesting novel - Marooned in Realtime - that follows a group of humans who missed the Singularity and have been "Left Behind" so to speak. Not Sing Fic, but a neat concept.
Come to think of it, there's a lot of post-Singularity fiction, but very little actual "in the Singularity itself" fiction that comes to mind.
OH! Chiang's short "Understand" is an awesome watching-the-singularity-happen story, and is available here: http://www.infinityplus.co.uk/stories/under.htm (Almost everything Chiang's ever written is brilliant, FWIW)
Did anybody else have difficulty reading Accelerando? I tried reading it once, found it boring and stopped after the first few pages, then later on got a considerably longer way in before quitting but it still took a bit of an active effort. Not sure of what the exact reason was, since I've liked some of Stross's other works (but not all of them).
I enjoy reading singularity themed sci-fi especially if it focuses on bootstrapping and power leveling. Most recently, I read Stross and Doctrow's Rapture of the Nerds ( http://craphound.com/rotn/download/ the third part is especially interesting), and the my little pony fanfic Friendship is Optimal ( http://www.fimfiction.net/story/62074/friendship-is-optimal ). I happened upon a link to the latter on this site and it was a nice surprise. However, I'd prefer to be kept abreast of new releases in this genre in a more reliable way and I'm guessing many others here would as well. Accordingly I propose that we exchange recommendations in this thread, or if there is already such a thread that somebody link to it.
-sS