Lost the plot setting up a mirror

[Roger Beever]

Hi
I'm trying to set up using a mirror site as per the how-to on
fedoranews.org but I'm a little confused.
If i want to use;
http://zeniiia.linux.org.uk/pub/distrobutions/fedora/linux/core/
I think I put "yum fedora-core-1 " +the url as above in
/etc/sysconfig/rhn/sources and the same for "updates-released"
But what exactly should I be putting in /etc/yum.conf 
Please.
Regards Roger