The training required for the North Pole Marathon entails the same basic training that is required for a regular road marathon.
There is a variety of training resources and plans on the Internet that generally involve schedules of 15-20 weeks preparation. Below is a selection of links to the recommended schedules of some of the better known authorities on the discipline. It is advisable, however, to extend your long runs as you will be spending more time on your feet at the North Pole.
Some links are:
Runner's World 10 Marathon Foundations
Runner's World Intermediate Training Plan