re numpy, it's pretty well converted:
$ py3
Python 3.1.2 (r312:79147, May 17 2010, 21:50:36)
[GCC 4.4.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import numpy
>>> numpy.test()
Running unit tests for numpy
NumPy version 2.0.0.dev8417
[... lots of output ... ]
Ran 2929 tests in 15.571s
OK (KNOWNFAIL=5, SKIP=4)
[?]
but yeah, there's not much motivation to switch now.
Hopefully they'll pep8 the names too.
Note this question was asked back in 2010, and is out of date. After a period of beta-level support for Python 3, Biopython first officially supported Python 3 with Biopython 1.62 (August 2013) which was done using the 2to3 conversion script, and as of Biopython 1.63 (December 2013) supports Python 2 and 3 directly with the same code base.