On my old blog, I detailed a method I developed under 10.2 to enforce a particular screen saver for all users and to prevent the average user from changing it. This allowed us to enforce a password protected screensaver that activated after a certain idle interval.
A recent post on macosxhints takes this method and builds on it. But the poster runs into an issue with Tiger's combined Desktop Pictures and Screen Saver Preference Pane – when he restricts access to the Screen Saver, he also loses access to the Desktop preferences. We can fix that issue.
If you want to secure the Screen Saver preferences, but still allow access to the Desktop prefs, you can do this (beware line breaks; each command beginning with 'sudo' should be all one line):
sudo chown root:admin DesktopScreenEffectsPref.prefPane
sudo chmod 750 DesktopScreenEffectsPref.prefPane
This prevents non-admin users from accessing either Desktop or ScreenEffects prefs. (and visually removes it from the System Preferences app for non-admins.)
Now to restore access to Desktop prefs (again, beware line breaks):
sudo cp -R DesktopPictures.prefPane /Library/PreferencePanes/
This copies the Desktop prefs pane to /Library/Preferences. It will now show up in System Preferences under the "Other" category.
This works because the combined Desktop/Screen Saver prefs pane actually contains seperate fully-functional preference panes inside its bundle: one for Desktop and one for Screen Saver.