If you haven't sprung for a word processor for your home computer, or if you just don't use it enough to install one on a secondary computer (like me), then you need to check out Writely, Google's new free browser-based word processor. Once you register, you can create and edit documents, and save them as Microsoft Word docs, Open Office files, or PDFs.
After about 2 minutes of playing, Mr. Awesome and I even figured out how to share a document and work on it simultaneously from our respective computers - his a PC and mine a mac. In over 10 years of using Microsoft Word, the closest I've come to actual document collaboration is putting a file on a network share.
From what I've seen, this has the potential to be a very big deal. Did I mention it's completely free?