"Fedora 9 features PackageKit for software management which can
tie into a number of back ends regardless of what method you're
using--UM, RPG, Apt, etc.
"PackageKit also supports on-demand software dependencies for
default apps, print drivers and more. For example if you download a
PDF file, but don't have a PDF viewer installed, when you try to
open the file PackageKit sees that you don't have a PDF Viewer and
offers to install the software you need--a definite win for the new