WallAgent is a Wallpaper Changer which changes your desktop wallpaper automatically like a slideshow or desktop changer. You can select wallpapers from either a remote server or your own computer. To take the hassle out of it, it's best to use auto mode which means that WallAgent will select a category and download all wallpapers for your desktop. The problem with this is that the quality can be very dodgy as it doesn't seem to discriminate between resolutions.
It's really nice though to be able to set your own photos such as holiday trips or family celebrations and watch them roll. It also has a very good looking Vista style skin which gives it an extra touch of class. Although it uses few system resources, I did find it very slow to respond however when I wanted to use the computer. Overall though, much less hassle than having to change your desktop background all the time.