A simple find in python ?

Continuing on my saga with my Python importer for xls, I ran into a situation where I had to dig in recursively into a directory structure and do something with Python. There seemed to be nothing easy in Python such as a 'find . -name '*.xls' -exec perform_task {} \;'. All of the solutions or suggestions that I have run across so far from stuff found in google seems to need me to perform some sort of mental or code acrobats. This is not to create a flame, I am just an intermediate in this so I am welcoming suggestions to do this if you people have any.