Cython is not a bad story for C interop, though. See e.g. pyevent (http://code.google.com/p/pyevent/), which provides Python bindings to libevent. Be warned: until there's a new release of pyevent (0.4), you should, in my opinion, use the SVN version.
Cython is interesting, but as cited, there are also some limitations and caveats. See http://docs.cython.org/src/userguide/limitations.html and http://docs.cython.org/src/tutorial/caveats.html