Fedora does not include MP3 support out of the box. This is because MP3 is a proprietary format. Fortunately, enabling MP3 support in Fedora 7 is very easy.
First thing to do is enable the Livna repository for Yum.
Run these commands as root
wget http://rpm.livna.org/fedora/7/i386/livna-release-7-2.noarch.rpm rpm -ivh livna-release-7-2.noarch.rpm
The next step is to install all the necessary libraries. This is what I did…
yum install gstreamer-plugins-ugly gstreamer-plugins-bad xine-lib-extras-nonfree