Our coach has begun giving the team weight work after practice a few days a week. I noticed a big difference when I began a regimented weight program of three times a week in college. It helped me in both cross-country and track. I would recommend use of light weights that you can lift comfortably for 12 to 15 repetitions.
Heavy weights build muscle bulk, a hindrance in distance running.
Avoid lifting on consecutive days. Also, it's a good idea to do weight work after running, not before you run, because after your run you'll be tired and less likely to overdo it in the weight room. Another benefit of upper-body strength is that you'll maintain efficient running form instead of breaking down, slowing your pace. Your ability to kick depends as much on good form as anything else.