We use Trac as project collaboration space within our company. We have been trying out agile-methodology (specially Scrum) for projects, but recently we went more formal with the approach using a software to manage the whole process.
We found ‘Agilo‘, a plugin for Trac, is easy to setup and was intuitive enough to get us started, considering our (no) experience with formal agile-methodology.
Do you want to get started with Scrum and don’t want to invest time learning a complicated software? You don’t need a software to do Scrum. However, if you like managing projects using a software and you are comfortable with Trac, try Agilo.
You might want to check Scrum in five minutes [PDF]
BTW! This is yet another post to spread the word about the software and tools, we find useful and have been using.
 project management, bug tracking, documentation, wiki and version-control browser