Here's the ones that I have.

100% free sex stories http://www.asexstories.com/sex-stories.html

Alt.Sex.Stories Text Repository http://www.asstr.org/main.html

FictionMania Main Entry Page http://www.fictionmania.com/
This site is focused on Crossdressing, Transgendered, Transvestite, etc. stories.

Literotica Erotic Story and Pictures http://english.literotica.com/stories/

Nifty Erotic Stories Archive http://www.nifty.org/
This site is focused on Gay, Bi and Trans stories