Learning Python: Code critique please

[macoovacany]

Hello all,
   I'm trying to learn various programming languages (I did MATLAB at
uni), and have decided to start with Python. The programming exercises
are derived from Larry O'brien's <a href="http://www.knowing.net/
PermaLink,guid,f3b9ba36-848e-43f8-9caa-232ec216192d.aspx">15
Programming Exercises </a>. First one is up with a couple of comments
of my own.

Any suggestions, corrections, things that I have done wrong, could do
better, etc, please feel free to post a comment.

Timbo