Presto: A project to add delta rpm support into yum for Fedora users
http://hosted.fedoraproject.org/projects/presto.  A list of presto-enabled
repositories is available there.

prunedrpms: A tool that removes all drpms that point to rpms no longer in your
            repository

Installation:
=============
1- Untar the package
2- Run 'make install'

Running:
========
1- Run 'prunedrpms <repo dir>' where <repo dir> is the base directory for your 
   repository