Up until recently, TriggerStreet was accepting only short films and screenplays. Since then, they've added plays and now short stories and books to their site.

From their e-mail to me:
"Since its inception, TriggerStreet.com has been the place to go if you wanted to find exposure and feedback for your Screenplays and Short Films online. Now, in addition to being able to upload your Short Stories to the site, a section we launched earlier this year, you can now also upload Books that you have written."

Normally a member must submit a couple of reviews of others' work before submitting their own, but there is currently a "free" period (meaning no previous review is needed) for short story and book uploads.

Creative Commons has a post that pretty much encapsulates what TriggerStreet is about, at
creativecommons.org/weblog/entry/4419

I haven't used the site, myself, but I became interested in it after seeing Kevin Spacey (who founded it) interviewed on the Charlie Rose PBS show a while back.