This is a super easy style. Start with a ponytail. Braid the top loosely, and then pull out the edges of the plaits to widen it. Gradually braid tighter to the end. This style probably would work better with very curly or kinky hair since you can braid further out to the ends without worrying about the ends popping out.
(I'm experimenting with some new software that came with my camera. I doesn't do much, so I need to keep searching for that old disk... This image is huge, and I can't put my blog stamp on it.)