This is definitely worth a look for Windows users. Free 'Browser in a Box' Runs Firefox 4 with Ultra Security | PCWorld Business Center
Originally created at the request of the German federal government, BitBox
(short for "browser in the box") runs on Windows XP, Vista and Windows 7 as well as Debian Linux, Ubuntu, OpenSUSE and Gentoo,
allowing users to surf the Web worry-free, Sirrix says.
......BitBox's security derives from the fact that the browser runs in a virtualized environment using VirtualBox 4.04 and a hardened implementation of Debian 6 Linux
. The included browser--Firefox 4--then runs in a separate virtual machine with its own operating system, keeping it completely separate from the rest of the user's system........
For users, BitBox is designed to feel no different from any standard use of Firefox 4. The software is available for free download by individual users
and requires no special expertise to install, Sirrix says. It's also available on DVD.