Fedora Core uses the yum mechanism developed in Yellow Dog Linux, and it works very well since there can be any number of yum repositories.
I just haven't had the time to update my Red Hat 9 box yet, so in the mean time I wanted to come up with a solution that would allow be to get security patches for Red Hat 9. I then found the Fedora Legacy Project. They maintain a yum repository for older versions of Red Hat linux, with newer software. Their instructions worked well for me.