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.
Thunderbird is a total redesign of the Mozilla mail component to produce a cross-platform, stand-alone mail application using the XUL user interface language. It has many new features, among them the ability to customize your toolbars the way you want them. a new look and feel with a large number of downloadable themes which alter the appearance of the client, and the ability to add UI extensions.