Mark Summerfield wrote a four page long summary of 2.6 to 3.1 differences. There is more on this under the google group where he made the announcement I am quoting below.
Newsgroups: comp.lang.python
From: Mark Summerfield
Date: Tue, 1 Dec 2009 06:03:36 -0800 (PST)
Local: Tues, Dec 1 2009 8:03 am
Subject: Moving from Python 2 to Python 3: A [...]
By Finn Arup Nielsen and created on August 28, 2009
Includes an interesting module usage on almost every page of the 65 page document, all readable online.
Samples
Downloading a Web Page
Reading the comma serperated vaalues
Adding the URL’s to a Python list
Reading feeds
Determine “interesting” words
Multivariate analysis algorithm
Python programming — introduction to Python –
