Someone requested a programs like this a while ago. I've set it to cycle through my large NSX wallpapers. 
<FONT SIZE=+1><A HREF="http://download.microsoft.com/download//9/C/1/9C1D6866-64A6-40C0-ADBB-A2B62D42CA4E/PowerToys_VSS.exe">Windows XP Wallpaper Changer PowerToy</A> [400KB]</FONT>
Wallpaper Changer PowerToy allows your desktop wallpaper to change automatically. Select the folder of images to display as a slide show and set the display interval to change wallpaper every few minutes, hours, or days
<FONT SIZE=+1><A HREF="http://download.microsoft.com/download/4/A/4/4A445A53-7E5A-44EF-A105-78809D9726D3/powertoys_wpchanger.exe">WinXP Screen Saver Power Toy</A> [183KB]</FONT>
The WinXP Screen Saver Power Toy makes it easy to play any playlist of videos as your Windows XP Screensaver.
<FONT SIZE=+1><A HREF="http://download.microsoft.com/download//9/C/1/9C1D6866-64A6-40C0-ADBB-A2B62D42CA4E/PowerToys_VSS.exe">Windows XP Wallpaper Changer PowerToy</A> [400KB]</FONT>
Wallpaper Changer PowerToy allows your desktop wallpaper to change automatically. Select the folder of images to display as a slide show and set the display interval to change wallpaper every few minutes, hours, or days
<FONT SIZE=+1><A HREF="http://download.microsoft.com/download/4/A/4/4A445A53-7E5A-44EF-A105-78809D9726D3/powertoys_wpchanger.exe">WinXP Screen Saver Power Toy</A> [183KB]</FONT>
The WinXP Screen Saver Power Toy makes it easy to play any playlist of videos as your Windows XP Screensaver.