qmail - [WWW] qmail is a fast, secure, feature-rich mail system.

Samba - [WWW] [FTP] Samba is an open source software suite that provides seamless file and print services to Windows (SMB/CIFS) clients. It is a cost effective replacement for Windows NT/2000 based file and printer servers.

PHP Classes - [WWW] The PHP Classes Repository provides a comprehensive collection of freely distributable classes provided by numerous authors.

PostgreSQL - [WWW] [FTP] Postgresql is another open source database. Although it started life before MySQL it has had a checkered history and never gained the recognition and popularity that MySQL has. However as of v7.x of Postgresql it has become a very solid, feature-rich database server.