Mpeg

# rpm -ivh http://download1.rpmfusion.org/free/fedoraPublish Post/rpmfusion-free-release-stable.noarch.rpm
# rpm -ivh http://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-stable.noarch.rpm

Now, Install all other plug ins..

# yum -y install gstreamer-plugins-bad gstreamer-plugins-ugly xine-lib-extras-nonfree gstreamer-ffmpeg

After successful installation, open Amarok or any other multimedia player and try to play the mp3 file and see if all goes fine and you are able to hear the music.

XMMS
To install xmms and make it MP3-capable, start by doing this:

# yum install xmms xmms-mp3

MPEG, QuickTime, AVI, and DVDs
MPEG (the format used on DVDs) represents itself as an open standard, but most Linux distributions won't ship software that read it because of blocking patents held by MPEGLA. AVI and Apple QuickTime have proprietary codecs covered by patents, so most Linux distributions won't ship software that decodes them, either.

Unfortunately, the alternate front end xine is even more broken. It can be installed this way:

# yum install xine xine-lib libdvdcss

Doing this will also install a number of support libraries, including the libdvdcss plugin

VLC Player:
# rpm -ivh http://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-stable.noarch.rpm
# yum -y install vlc