Usermin is a Web interface that can be used by any user on a UNIX system to easily perform tasks like reading mail, setting up SSH, or configuring mail forwarding. It can be thought of as a simplified version of Webmin designed for use by normal users rather than system administrators.
Usermin For Webmail is a modified version of the Usermin package that is pre-configured for use as a Web-based email client. It is designed to work on systems running a local IMAP server, such as Dovecot. By default, users can read email, setup autoresponders and forwarding with Procmail, filter mail with simple rules, change their passwords, and manage folders.
Virtualmin is a Webmin module that simplifies the process of setting up and managing virtual servers. It can create Apache virtual hosts, BIND DNS domains, MySQL and PostgreSQL databases, and set up Sendmail or Postfix to accept email for a domain. It can also manage mailboxes and mail aliases within a domain.