I saw a few of these moss balls with plants outside houses in Kyoto on my Japan trip earlier this year. I get such peace in mind by watching them. Have a look and get inspired.
The guy who made the kokedama designs in this video also has a blog with more great pictures. Check out Le Midori Design.Have a look at this video if you want to try making your own kokedama:
And here is a tutorial in English (Thanks Che'usa for sharing).