First of all I started out with the Couch to 5k program. If you don't run at all, and you want to, start here. It's amazing how you can go from running for one minute without stopping to running thirty. It's really amazing. I'd also say that if you have an mp3 player, download the podcasts which tell you when to run and when to walk, because clock-watching as every second ticks past does not do you any favours!
So at the end of Couch to 5k, what do you do? The next program is called Bridge to 10k, and bit by bit you increase your time (while your speed decreases, a necessity if you want to reach the end!). I've finished Week 2 of Bridge to 10k, and it's killing me! I'm not sure how I'm going to increase my minutes again in Week 3, but when I first began I never believed I could have run for as far as I now have... so I'm going to give it a go.
One day I'd love to run a marathon. I don't know if that can happen, but it's certainly on my bucket list :)
Look out for a plodder in your area, it might just be someone like me :)