Linux Administration

Bash Scripting
http://tldp.org/LDP/abs/html/

Debian Administration
http://www.debian-administration.org/
http://tldp.org/LDP/www.debian.org/doc/manuals/system-administrator/

Slackware Linux Essentials
http://www.slackbook.org/html/index.html

Slicehost articles and tutorials
http://articles.slicehost.com/

Apache tips & tricks
http://www.ducea.com/2006/06/26/apache-tips-tricks-disable-directory-ind...

Basic MySQL configuration
http://www.linuxhomenetworking.com/wiki/index.php/Quick_HOWTO_:_Ch34_:_B...

Load averages
http://www.lifeaftercoffee.com/2006/03/13/unix-load-averages-explained/
http://blog.scoutapp.com/articles/2009/07/31/understanding-load-averages