[CentOS] Yum site cache

Hi all, since I'm installing several copies of CentOS I was thinking of using some system to save bandwidth.

I started looking at mrepo, but I noticed that, if I let him sync with updates and rpmforge repos, I'll end with a _lot_ of unneeded files. Also I have to modify the various yum repos configuration files for it to work.

What I would like to achieve is just download the same file only once: does anyone know if there is something like a "yum proxy-cache" or if it is possible to instruct squid to caches at least the rpm's and to serve them regardless of the server (by default yum uses a server list, so it would be nice to have the system working without having to fiddle too much with config files)

tia

Lorenzo