I have been using the treadmil to do my c25k. Now that the weather is getting nicer I want ot start running outside and get used to running on roads to prepare for more 5K races. BUT how do you know how far you're going? As to counting miles etc??
Easiest way is if you have a GPS watch, which will keep track of the miles (and many other factors) for you.
if you don't have one, you can map your run on a computer, either before or after the run, to get the mileage. There are a number of websites for this, most of which rely on the Google Earth database. I've used Map My Run http://www.mapmyrun.com and RunningMap http://www.runningmap.com/