Anthill is a PHP-based bug tracking system similar to Bugzilla. It is easy to configure, easy to use, fast, and helps make dealing with bug reports less of a headache and will streamline any job you are doing related to bug or problem reports.
Version 0.3.0 supports the PostgreSQL database for a backend along with MySQL. Several improvements have been made and minor annoyances have been corrected, along with anti-spam measures being taken, filter-able headers in email messages, and a significant amount of debugging code to help track down any potential problems.
Apache (any version) or other Web server, PHP 4.2+ (4.3+ recommended), MySQL