Google Docs is a place to put your Word documents (or a document created by you within Google Docs) on the Web and access them from anywhere. However, there is much more that you can do with Google Docs. In addition, you can also work with spreadsheets, presentations, drawings, and forms. It's free, unless you exceed the storage limits. It has similar features of Microsoft Word and is pretty easy to use. If you have difficulty, there are help articles provided. You need to register for a Google account. One thing that's pretty cool is that you can allow people to not only view your document, but also to be able to edit it, if you like. This makes it a valuable collaboration tool.
Although it has been available to users since 2007 (according to http://docs.google.com/support/bin/answer.py?hl=en&answer=49008), Google Docs is fairly new to me. I began using it for another project in my ET630 class. I created a critical information literacy project for my fifth graders and made it available on the Web (I will post the address in a comment soon). To evaluate my students' products, I created a rubric in Microsoft Word and uploaded it to Google Docs. There is a link to the rubric for students to view on the project page. Viewers can not edit the rubric, for obvious reasons.