Paulo:
If you downloaded (mirrored) the entire updates directory, e.g.,
http://(mirro)/pub/fedora/linux/core/updates/3/i386/
then just copy it somewhere on the hard disk and change the file
/etc/yum.repos.d/fedora-updates.repo
such that the baseurl line looks similar to this:
baseurl=file:///tiger/home/erwin/fedora/updates/3/i386
Then, when you run (as root)
yum update
the update happens from the local update directory. If you only have the rpms but not the entire updates directory (with the "repodata" directory included) you can put the rpms into a local directory, obtain "createrepo-0.4.1-1.fr" from www.freshrpms.net, and create the repository info with the command
createrepo (directory of packages)
Then run "yum update" as above.
Once you have the repository, you can update other machines, using e.g. ftp or httpd
Hope this helps,
Erwin