How to mimic the "desktop slideshow" feature in Windows 7?

I've been using the Windows 7 RTM lately, and I love the new "desktop slideshow" feature that changes the desktop background at an interval. How can I mimic this behavior on other version of Windows? (I'm on Vista 64-bit, if it matters.) I don't need fancy transitions or other features, I just want it as close as possible to the Windows 7 feature without using up too many resources.

You could try either John's Background Switcher, WallPapa or Wallpaper Juggler.

The cool thing is that they can not only cycle through pictures on your computer, but also download pictures from different sites, like interfacelift or flickr.

I've been using Webshots from about Win98, in fact, I still use the same old version from back when (works even under Vista/Win7).
More modern programs don't offer anything new that I'd care for, all I want is a background change every set interval.
It simple, minimalistic and works well.

Link to the old version (v. 1.3.0.2991)

Webshots Website

They just don't make 'em like they used to.