Microsoft Office Web Apps - Try it's free

Microsoft Office Web Apps is a web-based version of Microsoft Office productivity suite. It includes the web-based versions of Microsoft Word, Microsoft Excel, Microsoft PowerPoint, and Microsoft OneNote. The web apps allow users to access their documents directly from anywhere within a web browser as well as share files and collaborate with other users online. Supported web browsers include Internet Explorer 7 or later, Mozilla Firefox 3.5 or later, Google Chrome and Safari 4.

Office Web Apps is available to its customers via three channels:

View this Video in High Quality here

Web Apps description (Slide show)

For more information, read the Microsoft article Using Office Web Apps in Windows Live SkyDrive

Sources : Wiki, Microsoft