David, I've done a very dirty script that add most famous third CentOS'
repos:
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# Add third part repositories for x86 arquitectures.
# Jordi Espasa Clofent.
#!/bin/bash
# check root id
if [ `id -u` != "0" ]; then
echo "Sorry, you are not root."
exit 1
fi
# add Karanbar Singh's repositories
/usr/bin/wget http://centos.karan.org/kbsingh-CentOS-Extras.repo -P
/etc/yum.repos.d/
/usr/bin/wget http://centos.karan.org/kbsingh-CentOS-Misc.repo -P
/etc/yum.repos.d/
# add Dag's repository.
/usr/bin/wget
http://dag.wieers.com/packages/rpmforge-release/rpmforge-release-0.3.4-1.el4.rf.i386.rpm
-0 /var/dag.rpm
/bin/rpm -Uhv /var/dag.rpm
/bin/rm /var/dag.rpm
# add Dries' repository
# There are several options. Uncomment correct option according your
interests.
/bin/echo -e [Dries]\\nname=Extra Fedora rpms dries - \$releasever -
\$basearch\\nbaseurl=http://ftp.belnet.be/packages/dries.ulyssis.org/redhat/el4/en/i386/dries/RPMS
> /etc/yum.repos.d/dries.repo
# install fastestmirror plugin to improve yum performance
/bin/echo plugins=1 >> /etc/yum.conf
yum -y install yum-plugin-fastestmirror
exit 0
--------------------
Feel free to modify and adapt for your needs. I hope it will be useful.
PD. Note is for x86 boxes.