Google Docs is an easy-to-use online word processor, spreadsheet and presentation editor that enables you and your students to create, store and share instantly and securely, and collaborate online in real time. You can create new documents from scratch or upload existing documents, spreadsheets and presentations. There's no software to download, and all your work is stored safely online and can be accessed from any computer.
Google Docs is particularly handy for teachers when revising students' work. It allows you and your class to track what changes have been made, save each revision, and collaborate in real time. And it's a great organizing tool: You can easily upload old documents in other applications to Google Docs so all your files are accessible in one place. Not only can your students create electronic documents and spreadsheets, they can also instantly access and edit each other's essays, post their work to a blog, publish it as a Web page, and create eye-catching presentations -- all within the same program. (Eduptopia)