pycsw exists as a package in openSUSE Build Service (OBS). Since release 0.1.0 it is included in the official Application:Geo repository.
See Also: Installing from an OpenSUSE Build Service
pycsw exists as a UbuntuGIS package in Launchpad
See Also: Installing on Ubuntu/Xubuntu/Kubuntu
pycsw is available on the OSGeo-Live project. The pycsw overview and quickstart provides further information on using pycsw in OSGeo-Live.