How to get packages not supplied by Fedora

[Mark Knecht]

Hi,
   Being sort of new to Fedora I'm not clear about how to augment
their up2date/yum environment with locations that supply RPMs that
they don't supply. (mp3 playback or mplayer, for instance.)

   Is there any sort of common document on how to make the envionment
more complete, andhow to make updates a bit easier to do? (I.e. -
other tools like Synaptic, etc. and places to point them.)

Thanks,
Mark