Below I have posted a basic plan that you can look over.
A person who starts this plan should already be able to run 3 miles at a time and about 9 miles weekly.
This is an 18 week plan, with a 3 day split (3 day a week running schedule).
If you print and use any of these plans you agree that you do so at your own risk. Marathon training is not for the faint of heart, literally. Check with your physician when starting any workout plan.
Maybe in the future I will post more challenging or speed focused plans. This one is one of the most basic plans possible to be able to just finish a marathon.
First Marathon Basic Training Tips