CentOS

Get the pre-compiled CentOS from: http://www.centos.org

Or you could compile your own Red Hat Enterprise 3 or 4 Linux by getting all the 100% GPL free-libre-opensource SRPMS from :
ftp://updates.redhat.com/enterprise/3ES/en/os/SRPMS/
ftp://updates.redhat.com/enterprise/4ES/en/os/SRPMS/

See http://www.osde.info for further help