Here's what NHS Choices have to say about their running plan, "NHS Couch to 5K":
This is a running plan designed to get complete beginners from couch potato to running 5k (or 30 minutes) in nine weeks. It is: - Achievable - starting with a mix of running and walking and building up slowly - Virtually free - all you need is a decent pair of trainers and an MP3 player (a regular mobile phone will do) - Easy - a motivating 'personal trainer' tells you exactly when to stop and start. The plan sets three runs per week with a day of rest between each run.
If you complete the 5k challenge and decide you want to pursue improving your fitness further, you might want to consider consulting a personal trainer for a personalised fitness plan. For Brighton & Hove residents, I highly recommend Tegan Simmonds of FitAz Personal Training.
You can call Tegan on 07786 546063 or email firstname.lastname@example.org for further information.