Bugzilla is a Web-based bug tracking application.
Bugzilla
Bugzilla is a Web-based bug tracking application. Written in Perl, it is used by a wide variety of companies, organisations and projects. There is a comprehensive list of its features available here.
Landfill is a site consisting of various demo installations of Bugzilla. If you are interested in trying out Bugzilla, this is a useful place to start.