When I started exercising in the morning I didn't eat anything until I'd finished, then I'd have a big breakfast straight after. Now I've really increased the amount and intensity of my exercise it depends what I've got planned. On days where I have a hard cardio workout (like this morning's 8 mile run) I will have something, whether it's a quick snack before I go out or taking an energy drink along with me. I also have a light snack (70 calories or so) if I can tell when I get up that I'm a bit hungry, even if my workout isn't too intense.
I always eat after though, no matter what I've eaten before