Web site for eBook development

I would like to start a web site where people can collectively work on writing an eBook on a certain topic. (Sort-of wikipedia-style)

What kind of software would be appropriate as a server? Are there freeware or open source programs for this?

We would probably needs discussion-forum software as well as something to manage submission and editing the book chapters.

Thanks.

Eric

P.S. Please forgive me if this is the wrong place to post this - I'm not sure where to ask.