In the March of this year, Google acquired "DocVerse," which's now called "Google Cloud Connect for Microsoft Office". Google's now making it to early testers.
"Those who've not yet made the full move to Google Docs and are still using Microsoft Office --with Cloud Connect, users of Office 2003, 2007 and 2010 can sync their Office documents to Google cloud, without ever leaving Office. Once synced, documents are backed-up, given a unique URL, and can be accessed from anywhere through Docs.
Once in Google cloud, documents can be easily shared and even simultaneously edited by multiple people, from right within Office. A full revision history is kept as the files are edited, and users can revert to earlier versions in one click," explains Google.
To take off all you need is a Google account!
Google Apps for Business customer interested in joining, can sign up.