Can I save Mac OS X updates for my network?

Thre is indeed a way you can do this and it demonstrates how the Apple engineers have also been thinking about this problem and trying to come up with a simple and easily deployed solution.

There are two steps required to get this to work, as you know: the first is to disable automatic updates on the other computers and the second is to learn how to save software updates from Apple (I want to say "from the mother ship" here!) so you can apply them later.

Let's start with the first. It's easy. Go to Apple --> System Preferences... and click on Software Update. You'll see this:

As you can imagine, simply uncheck "Check for updates" and close the window. That computer will now never automatically check for software or operating system updates.

For the second part, it can be a bit tricky because the Software Update application on the Mac doesn't make it obvious how to save updates rather than just apply them.

If there are updates, this is most likely what you'll see on the computer that's still checking automatically:

What you need to do is to click on "Show Details", which will give you a specific list of every update that's available from Apple for your particular version of Mac OS X:

Pay attention to the small triangle in the circle (it's to the left of the iLife Media Browser Update, for example): if you actually apply those updates you'll need to restart the computer, whereas the other updates generally just require you to not be running that particular program.

(tip: my recommendation is to always quit every program running on your Mac before you apply any system updates, even if it's just to a specific application like Keynote. One of the most common reasons for corruption post-update is having too much going on while system files are being modified)

Once you can see the updates, select one or more of them then -- and this is the secret insider tip -- click on Update and check out the menu that pops up:

You can choose to only download, only apply or apply and save the downloaded update. Since you probably want your computer to be the baseline updated system, your best option will be "Install and Keep Package".

Choose this and...

Once it's done you'll either have the update applied or just saved, depending on which option you chose.

If you decide that there's an update for an application that you just don't care about then you can choose "Ignore Update..." from the "Update" menu, in which case you'll see this confirmation:

The saved system updates you can now easily copy to the other computers or to a centralized server and apply them on an as-needed basis.