How do I set macport python to be default?

[Christopher Brewster]

The correct answer appears to have something to do with the ordering in the PATH variable but this does not seem to work for me:
(On Snow Leopard - I have installed python from python.org and from Macports)

PATH=/opt/local/bin:/opt/local/sbin:/Library/Frameworks/Python.framework/Versions/2.6/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/texbin:/usr/X11/bin

$ whereis python
/usr/bin/python

$ python
Python 2.6.4 (r264:75821M, Oct 27 2009, 19:48:32) 
[GCC 4.0.1 (Apple Inc. build 5493)] on darwin

$ /opt/local/bin/python
Python 2.6.4 (r264:75706, Dec 21 2009, 20:23:10) 
[GCC 4.2.1 (Apple Inc. build 5646) (dot 1)] on darwin

I have looked in the Macport FAQ and Howto but found no answer.

Christopher