MantisBT

MantisBT is a web-based issue tracking system originally designed for use by software development teams and their customers. However users have been using MantisBT for issue tracking and project management in a variety of environments including help desks, project management, TODO list management and others. MantisBT is unique in that it finds the delicate balance between richness in features while maintaining simplicity of usage, deployment and customization..

MantisBT is developed in PHP and stores data in a database server (of which MantisBT supports many different database servers). All you need is a supported database server (usually MySQL or PostgreSQL) and a web server (Apache, Lighttpd, IIS, etc) that can execute PHP scripts. It is strongly advised that a PHP accelerator such as APC or XCache is used to dramatically speed up the execution of PHP scripts. Thus MantisBT can be used equally well on Windows, Mac OS X, Linux, and BSD based operating systems.