I know this isn't common practice, but I've rarely used a training plan for races of distances 13.1 miles or less. I just ran a lot of easy miles, made sure to get in some speed work, with a good average of running days per week. For the most part, it's worked for me. The marathon though? It's a whole different animal. Training for a marathon without a plan can be disastrous. Googling for a plan will pull up names like...
