Training for my Marathon

I've been cycling, mountain biking and hillwalking for a long time but I've done very little running. So, I've got to get my body used to it. The biggest trick is going to be avoiding an injury. I've done one important thing - I went to see a podiatrist and got orthotics which support my frame properly. It turns out that I have a collapsed arch in my right foot which has been giving me issues when I walk downhill (in the mountains). So far, my body seems to be coping with running. I ran almost 7 miles yesterday and managed it ok. Bit wasted at the end of it - that was a fuel issue I think. Becky laughs at me because, as usual, I'm slightly obsessed with marathoning now. I'm sitting here watching the London Marathon (and wishing I was there). I've just finished reading Paula Radcliffe's autobiography. And I voraciously read every book about marathon training that I can find. I know a fair amount about training on a bike - so I just need to learn a bit about running now too.