Freehelpdesk is feature-rich help desk system designed from the ground up to meet the demands of help desk staff and their users. It is a Web-based system that can accept new calls from your users directly into the system. Calls can be tracked and searched to enable faster response times.
GLPI (Gestion Libre de Parc Informatique) is an information resource manager with an administration interface. You can use it to build a database with an inventory for your company (computers, software, printers, etc.). It has functions to make the daily life of the administrators easier, including a job/request tracking system with mail notification and methods to build a database with basic information about your network topology. It provides a precise inventory of all the technical resources (all their characteristics are stored in a database) and management and history of the maintenance actions and the bound procedures. It is dynamic and is directly connected to the users, who can post requests to the technicians.
WikkaWiki is a lightweight and flexible wiki engine allowing easy management of Websites, in particular collective Web-based projects: it provides an intuitive interface for modifying page content, tracking and comparing revisions made by single users, and setting user access privileges. It features W3 compliant XHTML and CSS output, several text formatting options, categories, a GUI for editing pages, support for images, tables, Flash objects, RSS feeds, FreeMind maps, advanced Access Control List management, referrers management, and text search functions. Designed for easy customizability, it aims at keeping its core as light as possible while maintaining an architecture that supports extensibility through plugin modules.
Interleave is a Web-enabled business process automation application. It enables you to model your business process like purchasing, project management, and contract management and make it available online. It's meant to replace processes which currently rely on paper, email, or spreadsheets and it has a very good workflow engine. You can create invoices, export to RTF and PDF based on templates, export to MS Excel, interpret incoming email, and publish your data to the Web.
PHP Trouble Ticket provides a centralized means of problem reporting and tracking in multi-user environments (medium to large companies, development groups, etc.). It helps direct problem reports to the responsible administrator(s), keeps track of the status of a problem being worked on, and offers an up-to-date list of recent changes applied. It aims to be widely configurable, easy-to-use even for those not technically inclined, and multi-language capable.
WebIssues is a multi-platform system for issue tracking and team collaboration. It can be used to store, share, and track issues with various attributes, description, comments, and file attachments. It is easy to install and use but has many capabilities and is highly customizable. Desktop and Web clients are provided.