Do you have any meditation books or tips you recommend for children?

Great question. I will follow.
My oldest son (6) will often ask to meditate with me (I meditate daily). Most of the time, I just do simple guided meditation that concentrates on a body scan for tension, followed by concentration on slow, relaxed breathing. He seems to really enjoy it – mostly, I suspect, because he sees it as “something Dad does”. But sometimes he really does seem more relaxed and focused following even a brief meditation.

Also, not a meditation book, but only somewhat-related…my kids really enjoy the Zen Shorts books. It often sparks some thoughtful discussion.

Yoga would compliment the meditation rather nicely…my son has autism, and I find that yoga helps him relax…

I am currently looking for some meditation cds and books for children so thank you for asking this question, if I come across any on my travels then I’ll certianly post them here

I have a CD set, it isn’t specifically for Children but it’s “Insight Meditation”, and one of the sections is a walking meditation – a guided meditation while you calmly walk, I do it just back and forth in the room—and it’s very, very calming, and I think it would be fine for kids, incl. one with Asperger’s.