The New York Times has a fantastic marathon training tool which helps you choose the type of training program appropriate for your skill level and lets you log your workouts. I'm using it for my second marathon.
I also like Hal Higdon's training programs, which I used for my first marathon. He doesn't pile on the miles like the official NYRR training program.
The biggest mistake I made the first time was not stretching enough. If you can also fit yoga or stretching into the "rest days" then you will have a much easier time with the running and avoid injury.
A good way to log miles is to use the gmap pedometer, which allows you to map out running routes and measure if you're going as far as you think you are. I have a few favorite routes, which I'll share later. It's important to measure your miles accurately because you're supposed to change your shoes every 200-300 miles. It really does make a difference, and for me, after running on asphalt and concrete, it came pretty quickly during marathon training.