Flower Show reports: String gardens
Here is a link to a DIY site that shows how to make them: http://www.designsponge.com/2011/04/diy-project-kokedama-string-garden.html.
It looks pretty easy. You just need a plant, some potting soil, moss, and string or monofilament line to hang them with. I also see that this site suggests adding some bonsai soil to the potting soil, which you can find at local garden centers like Northwest Seed & Pet.
The important thing to remember is that you will want to mist the plants once a day to keep them moist. Also, I read that since the moss doesn’t do very well in the sun, it’s better to select a plant that tolerates shady conditions so you can keep your string garden out of direct sunlight.