Decorators must read
Decorators is another one of those features that is easy to use and also easy to implement (once you know how). I proved to myself again, that it is very much easier in Python than one can imagine and that I am thinking too difficult again.
The must read article about decorators, that explains it all in depth and the different use cases is the article Python 2.4 Decorators by Phillip Eby.
Finally I am sure not only about how to use them :-).