[jqueryin]

I know the obvious solutions for very low level profiling are xhprof and xdebug, but there is a time and a place for doing one off profiling. I can also recommend PHP Quick Profiler, released by Particle Tree a few years back, if you enjoy shiny things.

http://particletree.com/features/php-quick-profiler/

This bad boy has one added benefit over the others: console logging. Along the same token, you could be using a combination of Firefox with the FirePHP plugin if you like the idea of logging PHP directly to your firebug console:

http://www.firephp.org