Mantis is an open source bug tracking tool that is as feature-rich and stable as it is free. It is written in PHP and works with MySQL, MS SQL, and PostgreSQL databases. Mantis can be installed on Linux, Windows, and OS X and can use nearly any modern web browser. More here

Here we go again, building upon that rock solid Ubuntu Server installation. If you haven’t already done so, you should read the first article in this series (”Installing Ubuntu Server 9.04“). Once you’ve read that (and followed the steps), you are ready to go for installing one of the easiest to use and most reliable bug tracking systems available from the open source community.