Find a big hill (20* - 30*) near your house that is about 1 mile long. Every day Strech, Sprint up it, walk down it, repeat: until your leggs start shaking. After a month, do it with a 5 pound dumbell in each hand, Increase the dumbell 1 pound every month. Make sure you don't go cheap on a good set of distance running shoes and change them every few months.

Distance runners are skinny because they do not increase resistance in their training. This was how we trained for the 2 mile race way back when I was in shape. Our runners were bulkier than most of the others but could keep pace and had twice the speed during the Kick "Last 400 meters". I generally dropped 30 pounds in 3 months and had no problems putting it back on in time for football season. All it took was tripling my calorie intake, cutting the running in half and weight training.

Good luck man, Wish I still had the knees to get rid of my beergut.