VMWare offers a free product called Browser Appliance, which is a virtual PC with Ubuntu Linux 5.10. It is aimed for safer surfing in a safe virtual environment using Firefox 1.5. The download is 258 mb in size.
To use the preinstalled Ubuntu image you need the free VMWare Player, which has now been released as a final version. The VMWare Player is available for Linux and Windows and allows starting existing images. To create new images you need the full product.
After every reboot the browser settings like history and saved passwords are being lost, as the image always starts in its original condition. This feature can also be deactivated.