Presto: A project to add delta rpm support into yum for Fedora users
https://hosted.fedoraproject.org/projects/presto/wiki/WikiStart
Most of the code base has been written by Marcel Hild <mhild@redhat.com> as
up2date/satellite-server delta rpm support. Code adaptation for yum done by 
Ahmed Kamal <email.ahmedkamal@googlemail.com>. Support for storing repository 
information added by Jonathan Dieter <jdieter@gmail.com>

Installation:
=============
1- Make sure deltarpm is installed on your system (yum -y install deltarpm)
2- Place the files in the following locations:
   share-presto => /usr/share/presto/*
   presto.py    => /usr/lib/yum-plugins/presto.py
   presto.conf  => /etc/yum/pluginconf.d/presto.conf)
3- Use makerepo/createdeltarepo.py to create a Presto repository on top of a
   normal yum repository.
   NOTE: createdeltarepo.py will NOT change any files created by createrepo
4- In your repository conf file, set deltaurl to point to your Presto
   repository (in most cases, it will be the same as baseurl).
5- Now install an old rpm from your repo using rpm, then try updating it using
   yum. The plugin should kick in, try to download the drpm, reconstruct the
   full rpm, and yum should install that

Notes:
=====
- The code is in an early stage. Minimal testing has been done.