If you have Workgroup Manager you can use Preference Manifests. Add com.apple.screensaver.ByHost and set your settings. This may help to get you started:
http://managingosx.wordpress.com/2008/02/20/mcx-vs-the-screensaver-and-leopard/
My Example:
Once:
Often:
idleTime integer 600
moduleName string ScreensaverName
modulePath string /Library/Screen Savers/ScreensaverName
Always:
askForPassword boolean true
Or push out the ByHost Pref in ~/Library/Preferences/ByHost But you have to have a script to change the name of the byhost UID number if your reimaging your machines with one image. If you have users with mobile homes or something along those terms you have to get it into the users home, probably with a a script.
My users get a new Home directory on login so all I do is push the new pref out to my client computers into the /System/Library/User Template/English.lproj/Library/ByHost/ folder and I have a script on login that changes the UIDs.
***** for the users having a new home on every login, but it saves me alot of headaches. We rarely have issues.
Hope one of these helps.
-Dan