Google Cloud Connect for Microsoft Office brings collaborative multi-person editing to the familiar Microsoft® Office experience. You can share, backup and simultaneously edit Microsoft Word, PowerPoint® and Excel® documents with colleagues.
It allows you save the Microsoft Office files to Google Docs. After installation, it sits on the toolbar and if you want to save the file to Google Docs you just have to click Sync. You can also change the syncing behavior.
More info and download is available here.