I have a /usr/local/bin/shutdown like this: su -c "shutdown $1 $2 $3 $4 $5"
Anybody can run shutdown, but they'll need the root password. If you want anybody to shutdown without password, make /sbin/shutdown a suid executable. Make shutdown a menu choice in your window manager for user friendliness. Don't do the suid thing unless *anybody* logging into your machine should be able to stop it! This includes logging in via network or possibly the internet. It is ok for an unconnected home machine though. Helge Hafting
