"Although it's still considered a work in progress, Google's online spreadsheet will offer consumers and businesses a free alternative to Microsoft's Excel application a product typically sold as part of the Office software suite that has been a steady moneymaker for years..."
W: http://www.smh.com.au/news/technology/spread-em-google-takes-on-excel/2006/06/06/1149359713087.html
To take a sneak peak tour of the application and to sign up: http://www.google.com/googlespreadsheets/tour1.html