For ABC (or others getting to the end of C25K and looking at where to go next).. here is a blog post from a running coach that talks about the 10% rule in running (or the fallacy of the rule) and gives some suggestions on how to add miles to start. He stresses once again that it is a long term thing, and pushing too high too fast can lead to injury risks.
How to Increase Mileage Safely: Forget the 10% Rule