I ran 10k through the woods and Royal Oak sans dog.
To get the intervals right I bought a program called IntervalTimer on the iPhone ($0.99). It worked great. I did 4 minutes running and 1 minute walks.
Overall I did not like the run-walk method. The continuous interval signals made me kept me thinking about the run, interrupted other thoughts and kept me more conscious about my fatigue. I started running for the next break rather than just losing myself in the run.
I'm skeptical. we'll see.