For the little ones, learning to knit can be cuddle time. You cast on, and they put their hands with yours on the big chunky needles, and together, with your hands actually doing the work, you knit a couple of rows. They begin to get the feeling of how the knitting works, and watch how to do it- a little knitting rhyme works well here- like, under the fence, catch the sheep, back we come, off we leap. It is not independent knitting, but it is a step, and it can be great mom-time, like reading a story. And if their attention span is short, no big deal, pick it up again later or tomorrow. It will be waiting.
Shewolfy, thanks for this. My boyfriend's young son desperately wants to learn to knit, but he doesn't have the attention span to do it by himself. He'll do one stitch then lose concentration so the next one goes wrong. In the end he gets frustrated with it and it upsets him. I'm trying this method, we're planning to knit something small together, like a scarf for a teddy, then I'm hoping that sense of achievement from completing a project will give him more self confidence with the whole knitting thing.