Needle felting

I recently read about needle felting in Martha Stewart Living, and I think I’d like to give it a try. Look at all the wonderful things you can make with just a needle and some wool! (Click on images for instructions/sources)

Embellished sweaters for the kids

Have any of you tried your hand at needle felting? Is it hard? Or perhaps, so addicting that you are currently wading through a pile of adorable handmade animals just to get through your house?