... was suggested under WikiForumsWanted
Hopefully, the wiki at LinuxChix will grow to fill this task: http://www.osdi.org/phpwiki/index.php
This wiki doesn't seem to exist anymore... I haven't been able to find it, anyway...
The site, http://www.linuxchix.org, has very similar appearance but doesn't seem to contain a wiki.
There is a very comprehensive Unix/Linux Beginner's Tutorial at http://mandrakeuser.org/. It covers just about everything.
Moved from LinuxCommandDirectory
This directory of Linux commands is from Linux in a Nutshell, 3rd Edition. Click on URL to get a list of 379 commands and get a description and list of available options.
http://www.onlamp.com/linux/cmd/
http://www.knopper.net comes with KnoppixLinux, a debian derived live linux system: You can download this bootable CD for free which turns your computer into an independend linux station, KDE windows included, most of your hardware supported. If you are in a LAN with DHCP server you can start surfing the web few seconds after booting.