Create multiple asset databases containing any information you wish to keep track of. Some examples: put all your IT infrastructure into the database, or if you are a building manager, put all your facilities equipment in the database. Can also integrate with other systems via plugins.
A base platform for building associative knowledge bases. Not a complete product, but a foundation to build your own.
A free PHP based help desk tool, translations in English and French.
a light weight helpdesk for small to medium size IT departments, includes inventory management.
Open source help desk software, designed for use from a Linux/Unix command line. Includes a full featured email interface for customers.
A help desk portal built with Ruby on Rails.
BugTracker.NET (Online Demo)
BugTracker.NET is an open source, web based bug or issue tracker written using ASP.NET, C#, and Microsoft SQL Server/MSDE. Includes a screen capture utility that allows you to capture a screenshot, annotate it, and post it, with just a few clicks.
Software bug and ticket system designed to use Subversion as it's backend database. Currently there is only a command line interface.
An open source help desk software package from the creators of the MySQL database. PHP based and of course uses MySQL for it's database.
Google Apps Help Desk Workflow
A simple script for giving your Google Apps account a help desk workflow.
Help Desk Lite
Very simple help desk software package for basic issue tracking. It provides two major functions, service ticket tracking and operator assignment.
A modern Rails based, mobile first, ticket system with email support.
Information Resource Manager
IRM is a free PHP based help desk and asset tracker designed for IT departments.
Information Resource Manager - GLPI Edition
This is the same system as above (IRM), but with some additional enhancements.
Zope issue tracker which also handles software bugs. The primary focus is on email communication and request tracking and management.
A PHP based, ITIL compatible service desk solution
Java based open source help desk application with an emphasis on modularity. It's also provides i18n support.
A Java/JSP based open source corporate help desk system.
A Java based open source issue tracking system.
A Django-powered ticket tracking system for small enterprise.
Liberum Help Desk
Web based help desk software package written in ASP and VBScript. Microsoft SQL Server or Access is required. Automatic case routing, email updates, and reporting.
An issue tracker written in Django
A full project system where the help desk component is just one aspect. Automatically integrates with Midgard CMS.
A free PHP support ticket system with multi-language support and a plugin API.
OS Ticket is a lightweight ticking system designed to be easy to setup and use. It's written mostly in PHP.
A trouble ticket system to track telephone calls and e-mails. Designed to allow your support, sales, pre-sales, billing, internal IT, and helpdesk to operate in one system. OTRS is open sourced under the A-GPL and is written in Perl.
A web-based software bug tracker. The design focuses on separating the presentation, application, and database layers making customization easier.
Redmine is a flexible project management web application. Written using Ruby on Rails framework, it is cross-platform and cross-database.
RT is an open source ticket tracking tool. It has a web based help desk portal as well as support for creating tickets via email.
A simple issue tracking system with command line, web and email interfaces. Also includes many other modules such as todo lists and sales lead tracking.
Savane is a Web-based Libre Software hosting system. It includes issue tracking, project member management by roles and individual account maintenance. The issue tracking handles bugs, tasks, support, news and documentation management.
A help desk plugin for the Simple Machines Forum system.
Sinergia is a open source framework for creating customized help desk applications written in C# .NET 3.0. It provides a base on which you can develop your own web based help desk solution.
SiT! Support Incident Tracker
SLA aware support incident tracking system, PHP/MySQL.
Uses the Subversion version control system to store issues within your software code repository. Uses the subversion client, but a web based interface is in progress.
SugarCRM Open Source
The open source version of it's commercial counterpart. Mostly a CRM system, but it can also handle light help desk duties.
Minimalistic web based project management and bug tracking tool. Trac also includes wiki functionality. Written in Python.
WATS Wordpress Help Desk Plugin
A Wordpress plugin for running a help desk within Wordpress.
Zentrack is a help desk, bug tracking, and project management system.
Every ticket in this system is a wiki page. Must integrate with a Zwiki to function.