Using the Wiggler in After Effects
http://www.macdesignonline.com/tutorials/aftereffects/marapr01_wiggle.html

Anderson, Chad J.W.
Mac Design Magazine
2005

Abstract:

The Wiggler is great when you need random keyframes applied to a layer's property. Scale, opacity, movement, even a plug-in's values can be 'wigglered.'This feature will save you from having to create dozens if not hundreds of keyframes if you're trying, for instance, to make a layer move randomly or flicker.