Before we both go down the same paths and duplicate effort, http://hg.python.org/sandbox/vs2010port/ has already completed the transition in terms of running the conversion, saving off the VS9 files, making some minimal code changes (errno module specifically), and has begun to fix tests. This is already done for 'default' aka 3.3.

8 tests failed:
    test_distutils test_email test_io test_os test_packaging
    test_pep3151 test_socket test_subprocess

The distutils and packaging test failures seem to be about differences in command line flags for some of the VS2010 binaries (looks like a link.exe issue in one). Most of the others are about remaining errno differences, and the subprocess issue is with too many files being open.