http://g.ho.st/
G.ho.st Inc was created in 2006 to develop the Global Hosted Operating SysTem, the world's only true Web Operating System. G.ho.st aggregates all of the new Web-based software applications into a free Virtual Computer, by providing a Web desktop, a single online file system, single sign-in, sharing and collaboration.
For anyone who wants their personal computing environment to be mobile the G.ho.st Virtual Computer (VC) provides the first real alternative to Windows – a complete personal computing environment hosted on the Web and accessible from any browser.