cat /etc/mrepo.conf.d/centos5x86.conf

[centos5.1-x86_64]
name = Centos 5.1 Server ($arch)
release = 5.1
metadata = yum
iso = /virtual/mrepo/images/CentOS-5.1-x86_64-bin-DVD.iso
os = http://mirror.fast-serv.com/pub/centos/5.1/
updates = http://mirror.fast-serv.com/pub/centos/5.1/