This thread is to bring to the attention various websites that are useful for using a linux machine as a great server. Feel free to post links and describe what the site holds in it for setting up a server.
http://www.pipeline.com.au/staff/mbowe/isp/webmail-server.htm - great resource for setting up apache, mysql, php, ssl, qmail (a mail server), and various services for mail (including imap and an easy-to-use web interface for e-mail)