Change current introduction in 1.1
WAS:
Mac OS X 10.4 comes with Python 2.3 pre-installed by Apple. However, you are 
encouraged to install the most recent version of Python from the Python website 
(http://www.python.org). A ``universal binary'' build of Python 2.5, which runs natively 
on the Mac's new Intel and legacy PPC CPU's, is available there.

IS:
Mac OS X 10.5 comes with Python 2.5.1 pre-installed by Apple. If you wish, you are 
invited to install the most recent version (currently 2.5.2) of Python from the Python website 
(http://www.python.org). A current "universal binary'' build of Python, which runs natively 
on the Mac's new Intel and legacy PPC CPU's, is available there.

And then, to line:
The Apple-provided build of Python is installed in 
/System/Library/Frameworks/Python.framework and /usr/bin/python, respectively. You 
should never modify or delete these, as they are Apple-controlled and are used by Apple- 
or third-party software.

ADD:
Remember that if you choose to install a newer Python version like this, you will have two 
different but functional Python installations on your computer, so it will be important that 
your paths and usages are consistent with what you want to do.

Done in r66350. Thanks!