Read John Bingham's "The Courage to Start" and then read "No Need for Speed", also by Bingham;
Start easy - a walk run approach is best to get your body ready for the new stresses it is about to experience;
Go to a good running store and get fitted for a pair of quality shoes. It's worth spending the money here - you need a comfortable ride;
Before getting started, accept that there will be bad days - forget about them;
Before getting started, accept that there will be outstanding days - remember them always; and,
Enjoy. Take in the sights, celebrate your accomplishments, no matter how small they might seem. New runners see great gains in fitness and endurance in a relatively short period of time - keep track of your workouts in a log or online so you can easily look back on how far you have come.
Most importantly, put one foot in front of the other, shut-up, and run.