Have a look in /var/cache/yum/
while "package manager" is busy downloading packages. Yum cleans up these .rpm packages after it has installed them. I think there is an option to keep these .rpm files - keepcache=1 ( or something
). I haven't yet tried it myself.
/var/cache/yum/updates/packages/ will start filling up with .rpm files while packages from the fedora-updates repository are being downloaded.