Beginner
Codecademy (www.codecademy.com)
Intro to Computer Science (www.udacity.com)
Learn Python (www.learnpython.org)
Learn X in Y Minutes (learnxinyminutes.com)
Learn Python the Hard Way (learnpythonthehardway.org)
Artificial Intelligence for Robotics (www.udacity.com)
Learn Python the Hard Way (learnpythonthehardway.org)
PEP 8 - Python Style Guide (www.python.org)
Modules and Packages in Python (www.learnpython.org)
Python Programming Beginner Tutorials (www.youtube.com)
Automate the Boring Stuff (automatetheboringstuff.com)
What is a Python ORM? (stackoverflow.com)
Intermediate
Full Stack Python (www.fullstackpython.com)
Think Python: How to Think Like a Computer Scientist (www.greenteapress.com)
Python Module of the Week (pymotw.com)
Advanced