Interval training is actually best for fitness results, fat loss and cardio health. I use an iPhone app called Micoach. It's free and Adidas make it. You go to their website and put your goals in and how often you can train and it generates a program for you. I went from not being able to run for a tram, to completing 10km in under an hour with less than 3 months of training. Can't recommend it more highly.
Getting back to the interval training though, it's less boring than a straight run and much more challenging too. But you will get results quicker.
Enjoy your new pursuit. Maybe look up some fun runs that are coming up and register to keep yourself motivated.