Microsoft has released Office Web Apps, a plugin for Firefox which is designed to bridge the Cloud version of Office with older versions of Microsoft Office, such as Office 2003 & Office 2007 .
The Office Web Apps Browser Plugin installs an add-on that enables Office documents to be opened directly from Firefox into the proper Office desktop application.
If you have Firefox and either Microsoft Office 2003 or Office 2007, this plugin enables you to open documents directly from Office Web Apps into the appropriate Office desktop application. For example, in Word Web App, clicking Open in Word results in the document being opened in Word 2003 or Word 2007. When the document is saved in Word, it is saved back at the web location where it was opened.
This plugin works with Mozillawith Firefox 3.5, Firefox 4.0, Firefox 5 and supports Word Web App, Excel Web App and PowerPoint Web App as well as Office 2003 SP3 and Office 2007 SP2. The plugin can be installed on Windows 7, Windows Vista (Service Pack 1 and 2) and Windows XP (Service Pack 3).
Note : This plugin is unnecessary for customers who use Firefox and Microsoft Office 2010.