A Man and His Mutt - http://www.melonfire.com/community/columns/trog/article.php?id=98&page=1 A good guide to the mutt email client.
Advanced Bash Scripting Guide - http://www.tldp.org/LDP/abs/html/ An in-depth exploration of the art of shell scripting
Breaking out of a chroot() padded cell - http://www.bpfh.net/simes/computing/chroot-break.html This page details how the chroot() system call can be used to provide an additional layer of security when running untrusted programs. It also details how this additional layer of security can be circumvented.
CTRL-ALT-DELETE Behavior Modification - http://www.cyberciti.biz/tips/linux-disable-the-ctrl-alt-del-shutdown.html Keep linux from rebooting in response to the three finger salute.
Linux eMail Server - Mail Transfer Agent (MTA) software - http://www.yolinux.com/TUTORIALS/LinuxTutorialMailMTA.html Internet mail is sent from the email client to the email server which routes it to the intended destination which will also be an email server. The protocol by which the email servers communicate is called SMTP (Simple Mail Transfer Protocol) and the email server software is known as the MTA or Mail Transfer Agent. This tutorial lists the popular MTA eMail server programs used, basic Sendmail email server configuration as well as Postfix email server configuration. Also listed are Mailing List programs and the RFC's (Request For Comments) on which the internet email standards are currently or eventually based.
Linux Man Pages - http://linux.die.net/man/ HTML versions of Linux Man Pages. If you don't know what these are, you probabably worry about viruses and windows updates every week.
Linux Newbie Guide by Stan, Peter and Marie Klima - unixguide.net/linux/ A great resource for those just starting out with Linux. LNAG and LAME have both helped me with some basic concepts in getting started with linux.
Procmail Strategies Against Spam - http://pm-lib.sourceforge.net/README.html Spam is a problem. This document contains a detailed analysis of various ways that Procmail can be used to combat spam.
Some VMware images - http://www.thoughtpolice.co.uk/vmware/ If you wish to try out several linux flavors without interruption to your current OS before you really install it, VMWare plus these images will do just that and bypass the pain of installing them in VMWare too!