totem should be installed , by default ( no non free codecs , though )
did you look on the red hat knowledge base ?
you will need the username and password you set up with the REQUIRED license
the music and video is in rpmforge repo and you MUST use " yum-priorities " and maybe " yum-protecebase" AND CONFIGURE IT !!!!!
rpmforge can come in conflict with RHN
you can install VLC for dvd's
Mplayer for videos DL'ed from the net
rhythmbox for music