Bug Tracking, Issue Tracking & Project Management Software – JIRA

http://www.atlassian.com/software/jira/
JIRA combines issue tracking, agile project management, customisable workflow, and a pluggable integration framework to increase the velocity of your software development team.

http://www.atlassian.com/software/jira/

Link: http://www.atlassian.com/software/jira/