My daughter was less than a year old when we watched her unlock my wife's iPhone and start playing with it. It wasn't taught to her, it was just natural "mommy did this, then this, so I will too and it works".
Moral of the Story: Kids are smarter than you think. (And they don' have a phobia of technology so they are willing to try anything)
Heard it suggested once that the reason older people are reluctant to explore and experiment with computers is that in their day, experimenting with the machinery of the time could mean a severed finger or lost limb.
There doesn't seem to be a clear understanding that short of taking a hammer to your computer, it's almost impossible to break...
Part of this is our fault also - we've allowed decades of software with bad defaults, no-warning data deletions, etc, and now people are afraid that a single stray button click will nuke their precious work.
She refused to touch it. She did what she had been explicitly told to do, but nothing else.
One day I was there waiting, and she asked if I knew anything about computers; I told her I did, and at her request helped her out with a few things. In return, she let me play around on the internet (over their shiny new ISDN line) while I was waiting. I'd take the opportunity twice a week to show her neat things, or answer her questions, and so on, and she seemed to be enjoying it.
One day, as the final choir practice was drawing near, she told me that she was having a lot of fun with her computer, and learning quite a lot. She had always been afraid to break it, and to have IT or the principal or whoever yell at her (well, not really, but you know). After playing around, she understood that not only was it not going to just break on its own, but also if it did, she could just ask me and I'd fix it, and no one would know.
By the end of the season, she had become the person everyone else in the school came to for help, not because she was better with computers, but because she was less afraid of them, and understood that it was a simple causal relationship - you do something, the computer responds. She began teaching the other teachers how to do things, giving mini-lessons or fixing their problems.
This is why I feel the iPad is going to be a hit. It lets you do quite a lot of what the typical person does on the internet, but at the same time, you CAN'T damage it, except physically. You can't break the OS, you can't get a virus, and you can't do most of the things I see computer users have problems with. You'll never 'lose' an app because a shortcut disappeared, you'll never lose a document because the 'Save As' dialog opened up somewhere new that one time, you'll never download the 64-bit version of an app on a 32-bit OS, or install a 32-bit OS on 64-bit hardware.
When users aren't intimidated by the computer, they can do great things. That's what I feel the iPad will excel at - being accessible and comprehensible to the average user.