If you have a dual-monitor configuration, you can set up a screensaver to move across both monitors, or duplicate on both.

Windows 7 does a pretty good job spreading its screensavers across two monitors, but Windows XP isn't quite so adept at it. Here are a couple workarounds.

Will you make it work on multiple monitors? Only version 0.1 of Really Slick Screensavers (at the top of the downloads page) is capable of running on multiple monitors.