Qmail

Anti-Spam Howto
Discusses anti-spam philosophies from a variety of perspectives and provides information about available options for dealing with spam within qmail.
http://www.summersault.com/chris/techno/qmail/qmail-antispam.html

Bayespam
A qmail spam filter which uses statistical word analysis on incoming email.
http://sourceforge.net/projects/bayespam/

Content Filtering with Qmail
Two scripts that allow content filtering on incoming email.
http://www.fehcom.de/qmail/filter.html

Creating POP Accounts
Setting up pop email accounts in qmail's Maildir format.
http://www.whirlycott.com/phil/pop3.html

Ezmlm
An easy-to-use and high-speed mailing list manager. Includes installation instructions, manuals, FAQ, version tracking, and source downloads.
http://ezmlm.org/

Helios qmail distribution
Advanced qmail distribution based on qmail-sql which has SMTP/ SMTPS/ POP3/ POP3S/ IMAP/ IMAPS services, antivirus and antispam filters, antispoof, SMTP-AUTH, SMTP-after-POP/IMAP, PHP5 API and many other useful tools.
http://helios-qmail.sourceforge.net/

lnter7
Provide commercial support of qmail and related mail services. Inter7 has supplied the needs of federal, state, global, and international operations along with small organizations.
http://www.inter7.com

Newbie's Guide to Qmail
A step-by-step guide to installing Qmail. Includes a complete shell script suite for configuring, compiling and installing Qmail and related Qmail utilities.
http://www.treachery.net/articles_papers/2001_04/qmail_newbie.html

Paul Gregg: Projects
Various scripts and an article on the userless mail hub configuration.
http://www.pgregg.com/projects/

Qmail: A Replacement for Sendmail
Dan J. Bernstein' qmail pages: information, software, coding philosophy, mail list information, surveys, win $500 if a security hole is found, and future plans.
http://cr.yp.to/qmail.html

Qmail Knowledge Base
A growing collection of links, questions and answers in a categorized, searchable format.
http://qmail.faqts.com

Qmail Mailing List Archives
Browse or search mailing list archives.
http://www.ornl.gov/lists/mailing-lists/qmail/

Qmail Man Pages
The entire set of manual pages.
http://www.qmail.org/man/index.html

The Qmail Newbie's Guide to Relaying
FAQs explaining relaying as it pertains to qmail, how to do it selectively, and some of the pitfalls involved.
http://www.palomine.net/qmail/relaying.html

QmailAdmin
A free software package that provides a web interface for managing a qmail system with virtual domains. Includes documentation and downloads.
http://www.inter7.com/index.php?page=qmailadmin

Selective Relaying with Tcpserver and Qmail-smtpd
Short article on relaying with qmail.
http://www.palomine.net/qmail/selectiverelay.html

SPAMbaffle
A SPAM filter for Qmail which can be installed by individual users or the system administrator.
http://spambaffle.com/

Virtual Qmail
BSD licensed package allowing you to easily administrate virtual domains under qmail. Includes CGI programs to use on you WWW pages.
http://v-q.sourceforge.net

Vpopmail
A free GPL software package to manage virtual email domains and non /etc/passwd email accounts on Qmail or Postfix mail servers.
http://www.inter7.com/index.php?page=vpopmail

Wikipedia: qmail
Encylopedia article with background, links, and details of controversies.
http://en.wikipedia.org/wiki/Qmail