KShutDown is an advanced shutdown utility for KDE.

Features:
  o Turn Off Computer (logout and halt the system)
  o Restart Computer (logout and reboot the system)
  o Lock Screen (lock the screen using a screen saver)
  o End Current Session (end the current KDE session and logout the user)
  o Extras (additional, external user commands)
  o Time and delay options
  o Command line and DCOP support
  o System tray icon and panel applet
  o Visual and sound notifications
  o KDE Kiosk support

WWW: http://kshutdown.sourceforge.net/