DBG is a a full-featured php debugger, an interactive tool that helps you debugging php scripts. It works on a production and/or development WEB server and allows you debug your scripts locally or remotely, from an IDE or console
You always can download and install the latest version of DBG PHP Debugger from http://dd.cron.ru/dbg/
The Xdebug extension helps you debugging your script by providing a lot of valuable debug information
Xdebug's built-in profiler allows you to find bottlenecks in your script and visualize those with an external tool such as KCacheGrind or WinCacheGrind