Tasks
When CHECK-TASKS is executed, it identifies the tasks to remind based on the current date and sends an email notification ONLY IF THE NOTIFICATION HAS NOT ALREADY BEEN SENT ON THE SAME DAY.
More Info 
Developer: Kwartik
License: Freeware
Operating System: Linux
TaskDriver is PHP/MySQL application that allows managers to assign tasks to assignees.
Developer: TBrillon
License: Freeware
Operating System: Windows
Sillaj is a PHP time tracking tool.
Developer: Michael Delorme
License: Freeware
Operating System: linux, windows, freebsd, osx, sun
GNU Hosting Helper is a web hosting management package.
Developer: Red Dragon Enterprises
License: GNU General Public License (GPL)
Operating System: Linux
The Account Services Manager allows web hosting companies to easily automate the time consuming tasks of managing mail, FTP accounts, and much more by giving the power to individual clients VIA a web based interface.
Developer: Account Services Manager
License: GNU General Public License (GPL)
Operating System: UNIX
ZeusCMS is a content management system that lets users build dynamic web sites using php and mysql.
Developer: Kerasiotis Vasilis
License: GNU General Public License (GPL)
Operating System: Linux, XP
Free software for contractors to manage their projects and tasks online.
Developer: Joe
License: GNU General Public License (GPL)
Operating System: Unix, Windows
RT is an enterprise-grade ticketing system which enables a group of people to intelligently and efficiently manage tasks, issues, and requests submitted by a community of users.
Developer: Best Practical Solutions LLC.
License: GNU General Public License (GPL)
Operating System: POSIX
Simple Customer is an open-source online customer database that allows you to easily manage your clients and customers along with adding notes and tasks & multiple contacts.
Developer: johnboyproductions.com
License: GNU General Public License (GPL)
Operating System: All POSIX (Linux/BSD/UNIX-like OSes)
Publish your properties in Internet & print them for your office window.
Developer: IT elazos S.L
License: GNU General Public License (GPL)
Operating System: Windows / Unix
GIMP is the GNU Image Manipulation Program.
Developer: gimp.org
License: GNU Lesser General Public License (LGPL)
Operating System: OS Independent (Written in an interpreted language)
Globulation 2 is an innovative Real-Time Strategy game which reduces micro-management by automatically assigning tasks to units.
Developer: globulation2.org
License: GNU General Public License (GPL)
Operating System: 32-bit MS Windows (NT/2000/XP), Linux, WinXP
epesi Business Information Manager is 100% web based open source CRM/SFA application that includes shared calendar, contacts, tasks, notes and more.
Developer: Janusz Tylek
License: MIT/X Consortium License
Operating System: multiplatform
TUTOS is _T_he _U_ltimate _T_eam _O_rganization _S_oftware, a webbased groupware or ERP/CRM/PLM system to manage your and your teams appointments, addresses, projects, tasks, bugs, mailboxes, documents, notes and your time spent with those things.
Developer: The Ultimate Team Organization Software
License: GNU General Public License (GPL)
Operating System: OS Independent (Written in an interpreted language)
Logikit::Framework (LF for short) is an application development framework for PHP 5.
Developer: Logikit
License: GNU General Public License (GPL)
Operating System: Not Available
MySQLMan is a web-based database manager.
Developer: Gossamer Threads Inc.
License: Freeware
Operating System: Unix, Windows, Mac
Fileman is Unix compatible.
Developer: Gossamer Threads Inc.
License: Freeware
Operating System: Unix
FileMan is a web-based file manager with an 'AJAXified' user interface that allows for complete management of a website without the need for FTP or Shell access.
Developer: Gossamer Threads Inc.
License: Freeware
Operating System: Linux, Unix, Windows
CalendarTechnique is a sleek, highly customizable, standards compliant web-based calendaring and scheduling application.
Developer: Caliberx Inc.
License: Freeware
Operating System: Linux, Unix, Windows
Wollabot is a modular service bot for IRC channels.
Developer: Christian Jørgensen
License: Freeware
Operating System: Unix/Linux/Windows