The yarn is Knit Picks Wool of the Andes Onyx Heather. I used exactly 4 balls.
It was difficult to get a good pre-felting photo, since it just looked like a gray blob. (I thought too late that I should have stuffed the unfelted bowl with something so at lease the shape was visible.) Christmas ornament included for scale.
I ran it through the permanent press wash cycle twice (about 16 minutes) with hot water before letting it rinse in cold water. I did pull it out before the spin cycle, since I have heard that can put creases in your project.
Once it is felted, you stuff the thing with something (I used plastic grocery bags) to shape it and let dry. I had a difficult time making it perfectly round and symetrical, but I don't think anyone but me will notice that it is slightly lopsided.
I did buy enough yarn to make two of these, on for my MIL as well, but I don't think I will get to it before Christmas. We'll see... I might just make it to keep for myself!