How about something like Sphinx?
You write your documentation in reStructuredText (the syntax is similar to Markdown, which Stack Overflow uses) into plain text files (=easy to version control) and Sphinx spits out HTML pages.
The two most prominent Sphinx users (that I know of) are the Python language and TortoiseHG (see the links for the Sphinx generated documentation).
I just read that you are talking about project-internal documentation, not end-user documentation.
In my opinion, something like Sphinx is the best way for internal documentation as well (provided that you can get your analysts to write reStructuredText) because:
- You can easily version control the documents (and diffs of text files take much, much less space than binary files like .doc or .pdf).
- If a developer wants a nice readable .doc or .pdf file, he can create it with Sphinx from the sources.
If Sphinx is too complicated, there is even an easier way: you can write your documentation in Markdown and use Pandoc to create (for example) .rtf, .doc or .pdf files (it can do a lot more).
I found Pandoc easier to get started than Sphinx, but Pandoc can't create nice menu hierarchies like Sphinx (like in the Python and TortoiseHG documentation I linked above).
No matter which of the tools you use, if you have an internal web server and a build server, you can set it up so that the build server generates HTML output and copies this on the web server each time someone pushes something to the documentation. So your analysts don't even have to think about the final output, they just need to commit and push their changes.