I started running (seriously) nine years ago. In every thing I have done and all the lessons I’ve learned, my first suggestion to you is invest in a quality pair of shoes!! The best move you can make is to find a running store to assist you in the purchase of the right shoes for your goals, your feet and your body type. Finish Line, Foot Locker, and the “chain” stores are NOT your best bet. Find a store that is dedicated to running (maybe tri’s) and have them analyze your gait and your feet. Then, hit the road. Soft surface, like a bike path (shale or dirt) or a cross country path will be easier on your joints, but the streets are okay. Please, please, PLEASE do not run on sidewalks. Concrete is NOT your friend and will ultimately cause joint damage. (But please do not put your life in jeopardy…always run safely!) If you’ve never run before, I’d recommend starting with a brisk walk. Gradually build in running. Perhaps 30 seconds to one minute for every 5 minutes of walking. As you improve and feel stronger, begin to switch the time intervals. Soon you’ll run five minutes and walk one minute.
As a runner with a pre-existing knee problem (before I ran) I STRONGLY encourage strength training to keep the muscles of the legs/knees strong. I have developed arthritis in my knee and although running does not cause problems with it, without strength training, it can become aggravated. Squats, lunges, leg extensions and curls, ad/abduction and all kinds of fun leg exercises are GREAT!!
Good luck and enjoy!!