[Discover] FirePHP - Firebug Extension for AJAX Development http://www.firephp.org/HQ/Use.htm
(php firefox debugging software) 
[Discover] PHP: var_dump - Manual http://docs.php.net/var_dump (debugging php)
[Discover] Zend Platform Event Debugging http://files.zend.com/videos/zend_platform3_demo_videos/event-debugging/ (debugging php programming)
[Discover] Live DOM Viewer http://software.hixie.ch/utilities/js/live-dom-viewer/ (dom tools tool debugging)
[Discover] debug css dom tool bar for ie http://www.my-debugbar.com/wiki/ToDo/Beta (ie dom debug css)
[Discover] PHP: var_dump - Manual http://docs.php.net/var_dump (debugging php)
[Discover] Zend Platform Event Debugging http://files.zend.com/videos/zend_platform3_demo_videos/event-debugging/ (debugging php programming)
[Discover] Live DOM Viewer http://software.hixie.ch/utilities/js/live-dom-viewer/ (dom tools tool debugging)
[Discover] debug css dom tool bar for ie http://www.my-debugbar.com/wiki/ToDo/Beta (ie dom debug css)