If you live in the world of Zope/Python, you might want to check out IssueTrackerProduct. This user-friendly issue and bugtracking web application looks to be a nice solution for tracking larger projects. It is free and open source, cross browser and cross platform compatible. And did I mention that it was free?
It looks to be maintained and updated very regularly which is a nice feature of any open source application. It also looks very easy to both install and use based on screenshots provided, although I have not actually installed or played with it myself. Still if you are any kind of an admin who might one day have a need for an issue tracker you should check this out.
