Started week 3 of my C25K (Sparkpeople's 5K Your Way) and let me tell you: my legs were SCREAMING the whole time! Last week's runs felt really good and easy, but adding that 30 seconds on per cycle really made a difference. It felt really good when I was finished though;-)
This weeks cycle has me walking in 3 minute increments still, but then running for 2. Day one and two I do 6 cycles and on day three I'll do 7. I'm still not seeing a ton of improvement on the scale, but in measurements I am and that's ok for me right now.
Remember, if you want to sign up for Sparkpeople, it is free and they have TONS of great resources! Just click the link I provided there and it will take you to the sign up page.