Getting into treadmill HIIT training...help please?

Hey guys!

So, I've been trying to shake up my cardio. I've started incorporating the treadmill, after months of sticking mainly to elliptical and spin class. The only official HIIT I've done is instructor-lead spin class.

I've been largely just getting used to the treadmill, because I've never run in my life as a form of exercise. I'll cycle between 5mph-8mph with a few 3.5mph breathers. I've never gone faster than about 1 minute of 8.5mph. I stay on between 20-30 minutes.

Now that I'm more accustomed to it, can someone give me a plan for treadmill HIIT? I'm not very familiar with it, as the instructor handles most of the schematics in class--you just have to do what she says.

So, what's a nice HIIT session that'll beat the crap out of me?

I'm trying to burn those final 15 pounds, so I need to pull out all the stops.