If you’re working with a team of people to build a software, a website, or a plain and simple group project, Bugzilla is a very good task management web based tool.
This web based app is pretty simple to use: you report bugs, change requests, new feature tasks, and calls for investigation, assign it to someone and follow this task’s progress until its resolution and QA check.
The really nice thing with Bugzilla is the number of applications you can find around it, from Firefox sidebar, desktop programs, Wiki integrations, and even a customizable firefox search engine. With bugzilla you can also have scheduled customized reports, email alerts, time tracking analysis, patch viewer, a nice file attachment management system, and many other features.
When starting to use it, I thought this was an incredibly confusing and poor application. But, giving some time and working with it more, I started to find it very resourceful. One thing I miss though is some extra features on its graphics and charts capabilities, those look darn right ugly and from my point-of-view, not very informative.