www.goowy.com/index.aspx

Includes email, contact manager and games, this service gives you an email address that you can access from your online desktop. Easily customizable, you can incorporate a lot of cool applications into this one platform.

desktoptwo.com

A desktop online, Desktoptwo includes many of the things you’ll find on your computer, such as a hard drive, email, IM, office programs and changeable wallpaper.

eyeos.org

A web operating system, this service lets you either download its software or use it through the eyeOS server. Includes a calculator, calendar, word processor and mail.