Hey, I agree with Scott, set yourself little rewards along your journey.
I completed teh C25K back in June 2012 and rewarded myself with a new pair of jeans and some new tshirts as my newly toned up figure meant my existing wardrobe had got loose. I also promised myself a running watch if I kept the running up for 6 months so in November, I bought myself a Garmin 110.
It is great motivation if you know you'll get a reward at the end or at specific milestones.