The blog post 'Using tweepy on AppEngine Python' from Bellicose Beliefs outlines how to effectively utilize the Tweepy library in Google AppEngine written in Pure Python. The post explains how Tweepy uses both basic and OAuth for Twitter API authentication and runs through the detailed steps to set up OAuth in your application, including creating an OAuthHandler object, generating the Authorization URL, and using request tokens. It highlights the fact Tweepy is up to date with Twitter APIs, supports Python 3, and is easy to understand.
http://code.google.com/p/codecontrol-samples/
http://codecontrol.blogspot.com/2009/09/using-tweepy-on-appengine-python.html