You can use Centos with yum for Oracle Unbreakable Linux. Use this on test instance only.
Move or delete other .repo files in /etc/yum.repos.d.
Create a file named centos.repo in /etc/yum.repos.d directory, containing these lines:
################## start
[base]
name=CentOS-$releasever
baseurl=http://ftp.nara.wide.ad.jp/pub/Linux/centos/4.6/os/i386/
gpgcheck=1
gpgkey=http://ftp.nara.wide.ad.jp/pub/Linux/centos/4.6/os/i386/RPM-GPG-KEY-centos4
[update]
name=CentOS-$releasever - Updates
baseurl=http://ftp.nara.wide.ad.jp/pub/Linux/centos/4.6/updates/i386/
gpgcheck=1
gpgkey=http://ftp.nara.wide.ad.jp/pub/Linux/centos/4.6/os/i386/RPM-GPG-KEY-centos4
################ end
You can change baseurl and gpgkey with other mirror. You can see list of mirrors here http://www.centos.org/modules/tinycontent/index.php?id=13
This script is for version 4.6. Change version number if needed.
