Learning Virtualenv in Python

Good references:
1. http://simononsoftware.com/virtualenv-tutorial/
2. http://iamzed.com/2009/05/07/a-primer-on-virtualenv/

about virtualenvwrapper:
http://blog.fruiapps.com/2012/06/An-introductory-tutorial-to-python-virtualenv-and-virtualenvwrapper