From Robin Rawson Tetley:
Animal Shelter Manager is a feature-packed, open source computer package. It is designed to manage all aspects of an animal shelter, including intake, adoptions, internet publishing, medical treatments, diary, reporting, and accounts. This is a complete, free administration system for animal shelters. This is very flexible and can be configured to match the workflow of any shelter. It can be installed locally on your computer or on a Web server for shared use by many people.