There are hardly any docs or tools for migrating C API modules from 2.x to 3.0. The one document that is available is incomplete and hard to find. This page is supposed to help people porting their modules from 2.x to 3.x.
Official docs here: http://docs.python.org/howto/cporting.html
Wiki with notes here: http://wiki.python.org/moin/cporting
Please add any issues or questions you have when porting to python 3 from python 2.x.
notes from psycopg2 developer porting to py3k: http://mail.python.org/pipermail/python-porting/2008-December/000010.html
One persons compatibility with python2.0 through to python3.0: http://pythonology.blogspot.com/2009/02/making-code-run-on-python-20-through-30.html
sq_slice handling... simple slicing was removed from the C API. Notes on how to fix it here: http://renesd.blogspot.com/2009/07/python3-c-api-simple-slicing-sqslice.html
NOTE: Another wiki page was created here (as a copy of the cporting doc in the official docs above): http://wiki.python.org/moin/PortingExtensionModulesToPy3k Best to update that page instead.