There's the official "What's New in Python 3.x" release notes [0][1][2] and some IBM articles [3][4].

[0] http://docs.python.org/release/3.2.1/whatsnew/3.0.html

[1] http://docs.python.org/release/3.2.1/whatsnew/3.1.html

[2] http://docs.python.org/release/3.2.1/whatsnew/3.2.html

[3] http://www.ibm.com/developerworks/linux/library/l-python3-1/

[4] http://www.ibm.com/developerworks/linux/library/l-python3-2/