TWIG  

Intranet/groupware tool and application framework. It is written and implemented completely with the PHP programming language. It intends to be a simple, cross-platform, fast, and browser-independent way to access or share almost any kind of information, without the complexity or costs of other intranet/groupware packages. Features: E-Mail (via IMAP); Contact Manager, Scheduling, Usenet Newsgroups, Todo Lists, Bookmarks and more.

Hosting Requirements: PHP 3/4
Price: Free

   PhpCollab  

Project management and collaboration over the internet. Features team/client sites, task assignment, document repository/workflow, gantt charts, discussions, calendar, notifications, support requests, weblog newsdesk, invoicing, and many other tools.

Hosting Requirements: Linux, Windows, MacOs X
Price: Free

   TUTOS  

TUTOS is a tool to manage the the organizational needs of small groups, teams, departments ... To do this it provides some web-based tools: a calendar for users and groups (incl. screenshot); Groups / Teams; address manager for people, companies and departments; bug tracking system; product/project repository; support of different roles (manager,developer,customer etc.); support of relations to other projects (base product, subproject etc.); mailboxes (imap/pop); timetracking on projects, installations and bugs; Invoices; Watchlists. Stay informed on changes on projects/bugs etc via email; support for teams that are distributed over different timezones; color schemes; fine grained permission handling; change history and more. All these parts are heavily linked together to give a unique interface for the day to day needs of people involved in project management and development.

Hosting Requirements: PHP 4
Database: PostgreSQL, MySQL, Oracle, Interbase
Price: Free

   PHProjekt - 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, chat, forum, request tracker, Notes, Bookmarks, Voting System and more. PHProjekt is available for over 25 languages and 5 databases.

Hosting Requirements: PHP
Database: Mysql, PostgresSQL, Oracle, Informix, MS SQL
Price: Free

   Axel Groups  

Axel Groups is a unique groupware application. It has an addressbook, a calendar, and other things you wold expect to find in a groupware application. It also has some other stuff you might not expect to find. Like a planner that actually makes a plan, or a project management feature, or a webmail front end. These things are all still pretty rudimentary in their development, but they work!

Hosting Requirements: LInux, Windows
Price: Free

   Group-Office Community Edition  

Group-Office is a Group-Ware suite containing a base system and different modules. The modules are designed in a way that groups of people can collaborate online. Group-Office is a modular system. It can be extended with modules. A module is a program that works with the Group-Office framework, Currently the following modules are implemented: Addressbook - Filesystem - Scheduler - E-mail client - Projects - Websites.

Hosting Requirements: LInux; PHP 4.1+
Database: MySQL
Price: Free (GPL)

   XenIntranet  

XenIntranet is a modular intranet/extranet solution based on the Ampoliros PHP web applications platform and taking advantage of Ampoliros features, like very fast deployment of solutions, a standard user interface, complete control and so on.

Hosting Requirements: Ampoliros
Price: Free (GPL)

   Magia Groupware  

Help your client's employees manage their emails, documents, calendar, notes, to-do list and more from one central location. Their information will be available anywhere they can login to the management area.

Price: ?

   ePersonnel  

ePersonnel was designed to replace the bloated, overcomplicated and aesthetically challenged Personnel Manager that many small companies use. With it's simplicity comes ease of use and clarity. Designed to help the everyday user feel at ease, it has a familiar XP style interface, even though it's completely web based. Features include: RTF document generation, absence management and statistics, employee management, user authentication. Added features to new RC include RTF document generation for automatic reference requests, error-trapping on employee forms, employee statistics, including probation & pension dates.

Price: Free

   Intra  

This intranet software is designed to allow one or many organizations to manage effectively data and information and to manage communications with the outside world. The software allows the formation of teams of users, message boards which can be posted to by email or online, polls, calendars, project management, file uploads, file submissions from the internet at large and more.

Hosting Requirements: *nix
Price: Free