Well, it's a cool tool for any day. From Google, it's Writely , an online word processor. You can upload existing Word docs, create new ones online, email them to your Writely account, then share the file with other folks for collaborative editing (or just keep it to yourself). Documents can be downloaded to your desktop in Word, OpenOffice, RTF, PDF*, HTML or zip formats, and you can also publish straight to your blog.
This could be a great alternative for libraries that don't offer Word on public machines. Sign up is free; they plan on integrating this into a Google account sign in, but currently you'll need a separate Writely account. After you sign up, they'll send you an email confirmation that you will need to confirm to activate your account, then you're good to go!
The editing screen looks a lot like a simple version of Word; the only problem I had came when trying to export my file - it took me a minute to realize I had to select the doc by checking its box before I could access the Actions commands (where the export options live). Their online help is a little slim, but there is a Writely Help Group  that seems pretty lively.