Postfixadmin

Postfix Admin is a Web Based Management tool created for Postfix. It is a PHP based application that handles Postfix Style Virtual Domains and Users that are stored in MySQL.

Postfix Admin supports:

Virtual Mailboxes / Virtual Aliases / Forwarders.
Domain to Domain forwarding / Catch-All.
Vacation (auto-response) for Virtual Mailboxes.
Quota / Alias & Mailbox limits per domain.
Backup MX.
Packaged with over 25 languages... (Thank you all for sending them!)

You can find more information on postfixadmin at

http://high5.net/postfixadmin/