Supposedly an exercise called a 'compression squeeze' will help with width. The idea is basically just laying your semi-erect penis on a flat surface and applying pressure, which theoretically expands the penis to the sides. It doesn't seem like anybody regularly includes this in a routine though, and it certainly sounds like something that could easily induce injury, so proceed with caution. I've tried this exercise before, and there is a very noticable immediate effect, but I seriously doubt that it's a good long-term 'grower' exercise.
I personally think that width has more to do with genetics, and although you might be able to increase it through overall girth improvement, I doubt that it's something that you can specifically target with Penis Enlargement. If you consider the nature of Penis Enlargement growth, even a 0.2" increase in girth is a fairly huge size improvement.