Google Chrome cartoon rocks!
I haven't seen the browser yet but Google Chrome's cartoon is the best description of o piece of software that I've seen in a long time. Kudos to Scott McCloud - someone should convince our local cartoon star or my friend MiBĂ© to do similar things!
Using graphics to explain stuff is obviously the best way, but the dynamics of the cartoon format (varying image sizes to emphasize importance, repetition of similar patterns and shapes to create a familiar universe in small steps) go much further than just combining images and descriptions. Not to mention the fun factor in reading it - everybody knows that people learn better when fun is involved.
I'm convinced - we need more of this to explain our often complex software systems.