Dice potatoes into small pieces. I use thin skinned potatoes and don't bother to peel, but if you prefer, peeled potatoes work well too. (The potatoes can be cooked in advance, or, of you want a really speedy meal, you could use the pre-cut pre-cooked diced potatoes from the produce section).
Boil potatoes in lightly salted water until soft, about 25 minutes. Drain.
Fry ham in heavy skillet over medium heat for about 3 minutes, flip and cook for a few more minutes, until there's a nice bit of juice in the pan. Add brown sugar to the pan, and turn ham to coat. simmer for about 5 minutes, turning occasionally, until ham is heated through.
Add potatoes to pan (you don't have to remove the ham, just lift it with a fork and put the potatoes underneath). Stir to coat evenly.