Often when folks start a new training regimen they go all out and often go too far. In pain, wondering why they ever tried to exercise, they quickly abandon their wonderful resolution to workout regularly. This is the exact reason that Cool Running created The Couch to 5K running schedule.
The program eases you into running 3 miles by combining walking and running together. Over the course of 8 weeks you increase your running time and eventually run for 30 minutes straight - about the time it takes to run a 5K. It is a great way to start running and the schedule has you running only 3 times a week - so easy to fit into any busy life.
Check it out and try the program - chances are you will get hooked on running. My only caution is 5Ks are considered a "gateway" race to marathons and triathlons.