APT is available for RPM based distributions (originally developed by Connectiva, but most useful on the biggest RPM based distribution - RedHatLinux).
All you need is the tool compiled for your version of RPM and access to a repository where rpm packages and their apt MetaData can be downloaded from.
(Is Apt broken after installing Ximian Desktop 2? See RedHatNotes.)
10 pages link to AptForRpm: