Antoine Ughetto has posted an easy way to find a file inside any series of subdirectories with PHP:

I've made a previus post on SPL using RecursiveIterator to parse Array. Today we will use this same RecursiveIterator with a DirectoryRecursiveIterator.

The code is pretty simple and straight forward - a DirectorySearch class that takes in the directory name and recurses through the files and subdirectories to locate the file you're looking for.