Is there a way to configure easy_install to avoid having to download the files again when an installation fails?
Update 13 years later:
easy_install was removed from Python in January 2021. The python package manager is
pip, it caches downloaded packages.
pip (http://pypi.python.org/pypi/pip/) is a drop-in replacement for the easy_install tool and can do that.
easy_install pip and set an environment variable
PIP_DOWNLOAD_CACHE to the path you want pip to store the files.
Note that the cache won't work with dependencies that checkout from a source code repository (like svn/git/hg/bzr).
pip install instead of