That's up to you and your body.. You just have to try it and see what works. If I don't eat before I go (even though I'm only up to 30 minutes at a time!) I feel sick and have been known to stumble on nothing at all and fall (granted, I'm hypoglycemic, but we didn't know that until recently).
Other people swear up and down that if they do eat before they go out, then they'll be sick..
Whatever works best for you.. I've actually been able to completely eliminate "bad days" (so far, going on 2 months) by running in the afternoons/evenings, around 4pm. It's a little strange..
Anything less than 8 miles, I don't need to eat before, only after.
For runs longer than 8 miles I eat approx. 1h30 or 2h before the run, mainly carbs and no dairy since it gives me bad gut surprises on the way...
You don't need to eat before you run, but if you want to, it should be several hours before. This will allow the food time to digest and avoid the insulin response that occurs within the first hour after eating.
It is important to eat soon after you run to replace the glycogen that you used during your run.
For short and mid distance runs, I usually go without breakfast. I've read several times that this allows you to tap into your fat stores rather than from the food that you consume prior to the run. (This assumes that you are working at a low to mod intensity pace). For long runs, I usually go without breakfast but bring some gels/drinks along the way.
I eat before and after. Something small to get in my stomach before and then a piece of fruit immediately after. Then I eat a small breakfast a couple of hours later and then I eat lunch