I'm developing a marathon training program for myself based on popular models and I'm trying to figure out how long the pre-training phase should be and what specifically I should try to accomplish during it. I've been running 3 - 4 miles a day for about 2 weeks so far. Are there any general rules about pre-training length and goals?
There are a number of good books and online sources that talk about training methods. A couple books are "Advanced Marathoning" (Pete Pfitzinger) and "Daniels Running Formula" (Jack Daniels). A couple good online sources are HalHigdon.com and McMillanRunning.com (the Running University section).
Maybe look at some of the Galloway training plans. Also, consider joining your local running group to connect with experienced runners that will most likely have some great advice and more personal suggestions to advance based on your individual circumstances, expectations, goals and so on.