Windows/Linux only: Firefox extension OpenXML Viewer opens Microsoft Word 2007 DOCX files directly in your Firefox browser. Granted, Gmail and Google just started converting DOCX files to HTML for easy viewing, but if you don't use Gmail or you stumble onto a lot of DOCX files linked elsewhere, this extension is a winner if all you want is a quick way to view a DOCX file. OpenXML Viewer is a free download, Windows and Linux with Firefox only. Be sure to check the README for instructions on how to enable OpenXML once it's installed. OpenXML Viewer [via Digital Inspiration]
