Jira - The #1 software development tool used by agile teams. Jira Software is built for every member of your software team to plan, track, and release great software.
Flyspray - The bug killer!
Redmine - Flexible project management web application
Collabtive - Collabtive is a web-based project management software.
Trac - Trac is a project management and bug/issue tracking system. Provides an interface to Subversion and an integrated wiki.
Teamwork - The Project Management App for Professionals. The most powerful and simple way to collaborate with your team.