On va faire simple :
[root@durandal ~]# cat << EOF > /etc/yum.repos.d/rpmforge.repo
> [rpmforge]
> name = Fedora Core 5 - i386 - RPMforge.net - dries
> mirrorlist = http://apt.sw.be/dries/fedora/fc5/mirrors-rpmforge
> enabled = 0
> gpgcheck = 1
> gpgkey = http://apt.sw.be/dries/RPM-GPG-KEY.dries.txt
> EOF
(en root tu tapes a partir de cat)
ensuite tu fais yum install --enablerepo=rpmforge install webmin