You have an plugin Antibuild. Where no registered users, can't build. I'm searching the same, but for can't do pvp. We have waves of English people that log in, and kill everyone. So i'm searching for a antbuild, but for pvp protection. Thanks
http://forums.bukkit.org/threads/fu...s-between-groups-and-their-members-617.11133/ You only need to add the "groupPvP.denyattack" permission node to the "New Players" Group.