OffiSync is a site that provides the ability to easier sync your Google Docs with Microsoft products (Word, Excel, and PowerPoint). OffiSync is a free download that integrates into the Office software.
OffiSync allows all the tools of Google Docs with Office, more specifically the sharing and collaboration aspect. My school does not use Google Docs, but I am often viewing documents from Google Docs via Twitter, so this software would allow me to easily integrate them into my Office software. To get a better understanding, you will probably be interested in the video below, that is also available for viewing on OffiSync's website.
For more information about OffiSync, and to compare the free and premium versions click here.