* Look into Apache Webdav. It will run over SSL and allow Windows users access.
* Depending on what your goal is, a CVS or some document management system may be a good solution.
* A Wiki? Something like Dokuwiki or PMWiki allow you to share all sorts of files.
I think there may be multiple solutions. That is, if you are willing to look at your problem from the perspective of what you are trying to accomplish, rather than trying to force a particular technology to apply to your problem.