diff -up ./setup.py.orig ./setup.py
--- ./setup.py.orig	2011-02-28 17:35:32.604468435 -0500
+++ ./setup.py	2011-02-28 17:35:55.914559618 -0500
@@ -1,9 +1,12 @@
 from distutils.core import setup
 
+__requires__ = 'Sphinx>=1.0'
+
 version = '1.1'
 
 # If sphinx is installed, enable the command
 try:
+    import pkg_resources
     from sphinx.setup_command import BuildDoc
     cmdclass = {'build_sphinx': BuildDoc}
     command_options = {