You could look at Zoho: <a href="http://www.zoho.com/productivity-apps.html" rel="nofollow">http://www.zoho.com/productivity-apps.html</a><p>That is the only alternative I know.
Check out Etherpad (<a href="http://etherpad.org/" rel="nofollow">http://etherpad.org/</a>). It's entirely open-source, so you can host all your own files on company servers/an intranet.<p>Certainly not a replacement for all of Google Apps, but it's a good start.