Linux Live CDs: All the Linux with None of the Commitment
Informit.com has a great overview of Linux LiveCDs. It starts by explaining the different uses of LiveCDs, and overviews many of the popular LiveCDs available today.
And if that wasnâ€™t enough, specialized live distros can run from business card-sized CDs, USB thumb drives, and some that are intended as rescue CDs for virus-ridden PCs. There are even live routers and firewalls in case you want to use an older PC as your main connection to the Internet.