The first step towards running is to establish a good walking base. You should aim at being able to comfortably walk 3 miles.
Spark's Walking Center is probably a good place to start. www.sparkpeople.com/resource/sparkwalking.
It depends a bit on your current level of fitness as to whether to start with the Beginners or Intermediate Walking plan.
When you are ready to transition to running, a Couch to 5K plan is definitely the way to go. These plans work through progressively increasing intervals of running and walking. www.sparkpeople.com/myspark/training-plans