Here is list of software that can be used for bug tracking or issue tracking.
- http://www.redmine.org/ RudyOnRails, lot of features. good one
- http://www.bugzilla.org Perl, bug tracking only. Very popular, large projects use it.
- http://trac.edgewall.org/ Python, popular, i see many medium size project use them.
- http://www.mantisbt.org/ PHP MySQL
- http://flyspray.org/
- http://webissues.mimec.org/ PHP MySQL
- http://etraxis.sourceforge.net/ PHP MySQL
See Scripts