I joined Jillian Michaels online and have been following her suggested circuit training. I first started out using her dvds b/c I'm a visual person and needed some guidance. Then went back to doing the exercises given online. The program consists of 5 circuits. Each one usually includes 2 strength and one cardio completing 3 sets each. An example: 15 reps of wide grip pull down, 15 reps backward lunges, and 1 minute of jumping jacks. Some circuits have a stomach exercise too.
Hope that helps and have a great day!