TrainRight is for you!
I have been part of TrainRight for around 1 month now, but have used Training Peaks in the past while I was bike racing and my coach required using the program. Since I have started running ultras and now moving into the 100 mile range I realized that I would need a bit more structure to accomplish my goal. So far I have seen my training fitness increase and the program I am on for running a 100 mile race is giving me the structure so that I can taper properly prior to my run.