Census Bug Tracking and Defect Tracking 

Census is a Web-based bug tracking and defect tracking tool that is fully customizable and integrated with VSS. Features include e-mail notifications, user/group/field-level security, role-based workflow, built-in reporting, and revision history.
bug tracking bug tracker defect tracking defect tracker issue tracking issue tracker bug tracking software bug tracking system defect tracking system defect tracking software defect tracking tool issue management

Defect Tracker 

Deliver software solutions to specification, on time and on budget with this powerful change management / configuration management / help desk solution. Tracks functional specifications / test cases / bugs and issues via the web.
configuration management configuration management software configuration management tools project planning change management help desk help desk software web help desk software software testing quality management software development tools