This Betfair client is an example/sample program that facilitates the navigation of markets on Betfair's Sports Exchange, and the placing, updating and canceling of bets. It is implemented in Python using version 6 of the Betfair Exchange API, and can be used with the Free Access Exchange API. It includes a re-usable class that wraps the exchanges.
I won't be implementing additional functionality in this example. However, there is another Betfair project that has used this one as its starting point: http://code.google.com/p/pythonbetfairlibrary/