ITauthor

I was intrigued to hear Dave Winer talking, in a recent TWIT podcast, about his FlickrFan program that get photos from Flickr and other Internet sources and shows them as your screensaver. Unfortunately this is Mac-only at the moment.

However, I found a similar program for PC:

http://www.codeplex.com/FlickrNetScreensaver

It's a little disconcerting not knowing whose photos are going to appear on your screensaver, but you can choose a tag (e.g. "nature") which lessens the scope for weirdness - like photos from someone's family holiday, or baby's Christening, showing up.