Linux Live CDs: All the Linux with None of the Commitment 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 wasn’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.

A little Linux can revive a pokey PC

The Los Angeles Times has a nice writeup on Damn Small Linux.

Apart from being compact and fast, however, DSL Linux may change the way you use your computer. For maximum speed to rehabilitate an old PC, you can install it like any other operating system, directly on your hard drive, either for exclusive use or as an alternative to Windows. You can also start and run it from a mini-CD, even if the host computer has Windows on it. So when you do visit grandma, you can take your DSL Linux with you.