PHProjekt - an open source groupware suite

PHProjekt is a modular application for the coordination of group activities and
to share informations and document via intranet and internet.
Components of PHProjekt: Group calendar, project management, time card system,
file management, contact manager, mail client and 9 other modules.
PHProjekt supports many protocols like ldap, soap and webdav and is available
for 36 languages and 6 databases.

WWW: http://www.phprojekt.com/