Flexible issue tracking system
Redmine is a free project management and flexible issue tracking system that you install on your own servers.
Redmine’s main features are:
* Multiple projects support
* Multiple subproject support
* Flexible role based access control
* Flexible issue tracking system
* Gantt chart and calendar
* Time tracking functionality
* Custom fields
* News, documents & files management
* Per project wiki and forums
* Repository browser and diff viewer
Redmine is open source and is also free.