depends on what you'd like to learn and how pretty you like to learn it. i was referring to the man pages to learn the apps such as XFree86.

google search: [insert OS]+manual

http://openbsd.org/faq/index.html
http://www.redhat.com/docs/manuals/linux/
http://www.slackware.com/book/
http://www.freebsd.org/doc/en_US.ISO...ooks/handbook/
http://www.gentoo.org/doc/en/handbook/index.xml
http://www.debian.org/doc/manuals/

to download linux:
http://linuxiso.org/