Screensaver when not logged in?

[Steven Lake]

	I know that the automatic screensaver kicks in when I'm logged in
an inactive for a while, but is there a way to set it so the screensaver
comes on even if I'm not logged in?

	Also, where do I change screensavers?  What file?

	Lastly, how do I set an automatic screensaver in Xwindows that
automatically locks the machine as soon as the timeout passes?  I'm using
KDE 3.1 and I want some way to automatically lock out my machine if I
forget to and walk away.