I don't know if its my installation because of upgrade or all Snow Leopard installations, but SL is asking frequently for the administrator's userid and password. When trying to do a Software Update, it asks before starting. On Leopard it would ask before installing, but not before checking. Seems unnecessary. I can't remember where but I've seen it pop up much more frequently than before. I've even had it prompt me twice during an application install. Even running XCode for development. Try and debug an application, it now comes up asking for the userid/pw or someone in the developer group. I don't see a built in app to configure who's in what group. Normal Unix group commands don't seem to be present.