Greg,
Does this change effect me?
My (default) yum.cong files point to mirror.centos.org. Do I need to point at different mirrors?
At about midnight Sunday night your time, I was experimenting with migrating RedHat 9 to CentOS-3. When I tried yum check-update, I got an error message that http://mirror.centos.org could not be found.
BTW, twice I tried to send this message to caos-mirror@casosity.org like you asked, and twice it came back immediately as undeliverable. (I copied and pasted the address.)
Rick