Here are some applications that are designed for and seem to target usefulness in the library setting. There are some general applications which are used in libraries as well, those are listed in the general section.
"Drupal is a free software package that allows an individual or a community of users to easily publish, manage and organize a wide variety of content on a website. Tens of thousands of people and organizations are using Drupal to power scores of different content.
open source wiki software
A simple web-based app for tracking library reference statistics
- CamStudio Open Source
Make Screen casts with this application.
LibX is a browser plugin for Firefox and Internet Explorer that provides direct access to your library's resources.