The Courier IMAP/POP3 maildir creation patch adds the ability to automatically create a user's home directory when he/she is successfully authenticated for the first time. It works by calling an admin-created script that takes care of creating the directory. It is quite useful in combination with authentication-modules based on network databases like MySQL or LDAP.
libspopc is an easy-to-use POP3 client library written in C. It implements the client side of RFC 1939, providing an easy and quick way to support POP3 and POP3s (SSL) access in a program. It can download email headers and delete messages remotely without actualy downloading the message.
Domain Technologie Control (DTC) is a Web-based control panel for hosting that can delegate the task of creating subdomains, email, and FTP accounts to users for the domain names they own. It has support for many programs, including bind 8 and 9, MySQL, Apache, PHP 4, qmail, Postfix, Courier, Dovecot, ProFTPD, Webalizer, and mod-log-sql. It can also generate backup scripts, calculation scripts, and config files using a single system UID/GID, and monitor all traffic accounting per user and per service. It is fully skinnable and translated into several languages.
Elm Millennium Edition is a text-based mail client. There are two branches: Elm 2.4ME+, which is based on Elm 2.4, and Elm ME+ 2.5, which also incorporates some code from Elm 2.5. Elm Millennium Edition contains enhanced MIME and character set support. A subset of UTF-8 (Unicode) is handled. It can read mail from a local mbox and POP and IMAP folders and can pass mail to the PGP or GPG programs. It can also view digests as a mailbox and reassemble fragmented (message/partial) messages. It includes modules for TLS/SSL, iconv, and SMTP.