Linux sites
Linux.org
Root.cz
ABC Linuxu.cz
Freshmeat.net
Gentoo Related
Gentoo.org
Gentoo x86 Handbook
Slackware Related
Slackware.com
Linux How-To
Gentoo Basics
Slackware Basics
*buntu Basics
Linux Commands
Linux Configuration Files
Kernel Compilation Guide
Example of Linux Firewall