Douglas Clifton has the next part of his "PHP Specificity" series posted today - a brief look at debugging in PHP applications.

In this fourth installment of the PHP Specificity series I'm going to break from the theme of content management packages momentarily and get into a topic that is not so dear to the programmer's heart. Debugging is a necessary evil and can be painful at times. But the reward, when it happens, is that eureka moment when you find the bug and squash it.

He mentions two helpful tools - DBG (though dead?) and the very popular XDebug that includes a profiler with Cachegrind output.