Prism extension for Firefox: Treat any web app as a desktop app
The most noticeable change is that Firefox 3 beta users don't need to download and install Prism as a separate application. They can just install a new Prism extension for Firefox 3. Once installed, you can visit any web site in Firefox and convert it into an application and place a shortcut on your desktop or in your start menu.
If you're not using Firefox 3, you can download the standalone installer for Prism 0.9 for Windows, Mac, or Linux. The latest build also includes the ability to pick an icon for your shortcut, and create a separate profile for each web application.