Zoho is an online Office productivity suite which consists of the following online applications:

Zoho Writer- Word
Zoho Sheet- Excel
Zoho Show- Powerpoint

With this service, one can create Office documents online and access them from anywhere through web browser.

Now Zoho is offering a free plugin for Microsoft Office 2003/2007 suite that allows you to Save any Word and Excel document from your computer directly to Zoho’s online server so that they can be access from anywhere anytime

Download here