There's a lot of ficlets over at the Watchmen kink meme (http://spam-monster.livejournal.com/813.html) (including some decidedly non-kinky gen; it seems to basically have turned into a "kinks, crack, and ficlet prompts" meme).

ff.net reportedly has some fic, but apparently much of it is in the "Dark Knight Joker/Mary Sue fic, take II" vein.