On Windows, Enfold Desktop is a nice solution, it blends in with your Folder and Network browsing. On Linux and Mac it can be accomplished with WebDav (which is available on Windows XP and 2003 Server, but ED is much nicer).
Zope has to be configured as a WebDav server. Add this to your buildout:
See http://plone.org/documentation/how-to/webdav/ for more on Webdav and see http://svn.zope.org/Zope/trunk/src/Zope2/utilities/skel/etc/zope.conf.in?view=markup for details about configuring your Zope's settings.
When testing WebDav locally, i found that going to localhost doesn't get me anywhere: i need to specify an IP (127.0.0.1).
Changed documents are uploaded immediately. "Page" types are shown in the WebDav folder as ".html" files, but they're really just text files with an HTML part in it, so they're not easily editable for users.