Just re-read the above and realised i've been a right numpty and got people mixed up!
Allan - as a runner, its a good idea to do cross training to help build up leg strength, eg squats and lunges and calf raises, although you prob shouldnt need to add weight, body weight should be sufficient. If you do add weight, make it light and stick to more reps.
Body builders use big weights and low reps to build muscle mass, you dont need that.. As mentioned above, hill work is really good, as is off road running as you use more muscles, and cycling for cross training. To build speed, faster intervals are good.
I think most of the training advice is about twice a week, but am not sure, dont know if its ok to do on same day as run or if you should do it on a rest day? perhaps someone can advise on if it makes a difference?
Roadrunner if you want to build muscle size, then do less reps with more weight. (typical muscle building would use enough weight that you can only just do 10-12 reps, for 2 sets, if you can do more, the weight is too light) When running, i guess sprints would be the thing?
Edited: 22/01/2013 at 10:04