Hi there, yeah I ran everything up to marathon. In 2005 I ran my first and only marathon cause I found it very boring. As I was running 3 times a week already I didn´t train that much. Just two 30km runs weeks before the marathon. It depends on if you want to run the distance no matter how fast/slow or if you want to run 3:59hrs for example. There are many good running forums on the net with runners who could tell you about marathon training plans.
runnersworld has a widget on their site. All you do is type in the date of the race and how hard you want to train and it spits out a customized training plan for you.