GShutdown is a utility that allows you to schedule shutdown, logout, and reboot for your computer. It is compatible with GNOME, KDE, and XFCE. In KDM and GDM, you can shutdown or reboot your computer without the need to be root. You can choose a command to stop the computer (like "sudo poweroff"). It has a systray icon with visual notifications. There are 3 different ways to schedule the action: at a time and date, after a delay, or now. There are command line options to change the default values.
OpenSuse 11.1 user can use "1-click" installer - here or if you already subcribe to packman, go to yast -- software management and search for "gshutdown" (shown below)
After successful installation, go to terminal and fire the command # gshutdown and you should see something like ..
There are lot of other option that you can configure for shutdown.