rpm -Uvh http://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-stable.noarch.rpm http://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-stable.noarch.rpm
Install unrar by doing this while being root
yum install unrar
Follow the prompts by answering “y” to finish the installation. You should now be able to extract or create rar files using the standard archive manager.
http://www.hackourlife.com/rar-unrar-support-for-fedora-15-lovelock/