In addition to the above, here's a website/article that I stumbled across a long time ago, and I'm still impressed with the valuable information:http://www.fitnessintuition.com/howtorun.htm
The author seems to have hidden the link to that page or spread the content throughout his newer blog (as I said, I found this page a long time ago).
Back when I first started looking around, the article above was the first I found that extolled the virtues of the run/walk strategy; his specific ratio is 5:1 (run 5 mins, walk 1). It is still amazing to me how many people still think any amount of walking is inferior; yet doing the walk/run strategy it's often much more efficient.
Well, have fun. If you come across any good information on this topic, feel free to post it here.