http://www.gozen.com GoZen! is an organization dedicated to the relief of childhood anxiety. To this end, we provide a unique online course that uses engaging animations to teach kids how to understand, manage and control their anxiety.
Videos include topics for: meditation, yoga, mindfulness and a "Dear Anxiety Podcast"
Kids respond really well to progressive muscle relaxation. Sometimes the pre-recorded versions are not my bag.
Here's one you can read to your child at night, pausing at the right spots, ad-libbing if necessary, and providing the soothing voice that your child knows and loves.