OK here's your link;
http://dag.wieers.com/home-made/apt/FAQ.php#B
Follow the directions and install the rpmforge-release rpm package and GPG key when done as root or equivalent do..
Install the downloaded rpmforge-release rpm package from where the file resides type something like;
rpm -Uvh rpmforge*.rpm
Now you can install either or both by typing something like;
yum install mplayer xine