twig
- An opensource groupware/intranet application focusing on simplicity and being cross-platform / browser-independent.
- http://www.informationgateway.org/

Neo Japan International GmbH - iOfficeV4
- A full featured commercial web based groupware suite that aims to improve communication and information sharing for groups.
- http://www.neoint.com/ioffice/

e-Bills - billing application for Linux
- The home of e-Bills, as web-enabled billing application for Linux using PHP and MySQL. Contains downloads and application information.
- http://www.asplen.co.uk/billing

groupware PHProjekt
- Open source groupware suite with calendar, project management, request tracker and 12 other modules. Supports more than 20 languages. Requires mysql, oracle, postgres, interbase, ms-sql or informix db.
- http://phprojekt.com/

phpGroupware
- Open Source collaboration software written in PHP. Includes features such as email, shared calendar, task list, address book, inventory, trouble ticket system, and many others.
- http://www.phpgroupware.org