It's probably been linked before in this thread, I stayed up late last night watching all 28 parts of the Dayz Guide Series. It's from a few versions back, but it shows how to behave when moving through areas thickly infested with zombies. If you're trying to decide whether to buy ARMA II just for this mod, these gameplay videos give a very good idea of the scale of the map (HUUUUUGE) and the general gameplay.