Central repository w/approved packages for local Ubuntu network
 

So far I have been doing manual updates, but our network is growing rapidly, with several virtual server clones being planned. Can anyone point me in the right direction? I would like to be able to review packages for updating before making them available to multiple Ubuntu installations from a local server for automatic updating.

Thanks in advance!

Have you looked into landscape or spacewalk(nee satellite). (Well more so landscape in your case) They're nice for managing largeer networks of workstations and servers.

You could also simply point all the servers to a local repo that you manually update after testing the packages and have the systems update off that repo on a regular basis and mail you a report about installed packages that you could parse and examine to ensure things were occurring as expected.