The passwordmetrics module takes a string and gives you a lot of information about it pertaining it's usefulness as a password.

• Free software: MIT license
• Documentation: http://passwordmetrics.readthedocs.org.

• Gives you a lot of information about a password, such as:
  • Words used in the password
  • Entropy (ie, how hard it is to guess)
• It's configurable for different languages.
• A big english wordlist included.
• L33t compatibility