[Update 2007-09-01]

These are available here: http://www.python.org/dev/peps/pep-0020/ as a Python PEP.

 

19 principles behind Python from Tim Peters: http://www.python.org/dev/culture.html

Of the 19, these 9 are my favorites:

Beautiful is better than ugly.

Explicit is better than implicit.

Simple is better than complex.

Complex is better than complicated.

Flat is better than nested.

There should be one -- and preferably only one -- obvious way to do it.

Now is better than never.

If the implementation is hard to explain, it's a bad idea.

If the implementation is easy to explain, it may be a good idea.