Nah, I do ultras to prove the point that anyone can do ultras :) It's good to meet you on Wellsphere, Allen!

A general statement is to be sure you're stretching to strengthen your knees and hips. The hips are important because they control the movement of your knee cap. Here is the link to my picture page of the stretches I do.  http://runninginjuryfree.org/2008/09/pictures-of-stretch-exercises.html  Always follow the 10% rule in increasing your distance. That is, make small increases in distance, typically around 10% increase, and don't do increases more often than once a week or longer. This means that it would take you several months to go from 5 miles to 15 miles in distance.

I'll definately give the negative splits approach a try Allen.  That's what I should have done in the one I ran last week but I did sprint the last 200 meters or so and that felt just great!  Do you have any suggestions for knee pain.  I'm not sure how to describe the type of pain I'm experiencing but it only my left knee at the moment.  I have been wearing a flexible compression type knee brace and I also wear compression socks as I early on had problems with shin splints which have now subsided. 

The pain in my knee is mostly towards the outside of my left knee.  It's not so bad I can't "run through it" but if I overdo it, it can last a couple of days.  It most often happens about 3 miles in and doesn't go away until I stop running and then I limp slightly for a while after but nothing a bit of Ibuprofen can't take care of.  I would really like to try a 25K next year but with my knee giving up around 5 miles, going till 15+ seems out of the question at the moment.  Any suggestions would be appreciated!