WiringPi is an attempt to bring Arduino-wiring-like simplicity to the Raspberry Pi.
The goal is to have a single common platform and set of functions for accessing the Raspberry Pi GPIO across multiple languages. WiringPi is a C library at heart, but it's available to both Ruby and Python users who can "gem install wiringpi" or "pip install WiringPi" respectively.
Python users note the 2 on the end, the WiringPi-Python library finally brings a whole host of existing WiringPi functionality to Python including brand new features from WiringPi 2.
WiringPi uses its own pin numbering scheme, here you'll learn how WiringPi numbers your GPIO pins, what those pins do and how to do shiny things with them from within Python or Ruby.
Installing to Python couldn't be easier, just:
sudo pip install WiringPi
For more information about WiringPi you should visit the official WiringPi website.