I've only used Knoppix a little. It is free & runs off a bootable CD.

http://www.knoppix.org/

Here is a Knoppix Forum:

http://www.knoppix.net/forum/

Here is a standard Linux site:

http://www.linuxiso.org/

And forum:

http://www.linuxquestions.org/questions/index.php

Here is an ISO recorder to burn your disk with:

http://isorecorder.alexfeinman.com/isorecorder.htm

Hope this helps.