Knee pains only on long runs - advice?

sorry for another knee pain topic but i couldn't seem to find any old thread that discussed the type/location of pain that i'm encountering.


as my training runs are getting longer leading up to my first IM (florida) my knees are starting to get painful around the knee cap (shown in this pic:

the red is the worst pain area, followed closely by the yellow area.



thoughts??
is this kind of pain/location of pain an indication of a certain injury?
is it just the increase of mileage and my body not used to it?
is there something more i can do to prevent this kind of pain?? (currently i try to ice for 15min then wear compression tights for an hour after all long/hard runs)
i plan on getting new shoes soon (current ones have around 225 miles on them), should i look for a different type of shoe? (Brooks Defyance 3 are my current shoes)
would a knee brace or knee taping help with the pain? (i only have 2 long runs scheduled and then the race day mary this year)



i just completed a HIM on saturday. i ran fairly strong but the entire last ~4 miles my knees were really aching. i averaged 9:21 on the run which is pretty good(for me). but the pain seemed to slowly increase and i'm worried it will be much worse on my full IM.
i plan to walk longer for each rest stop during the IM as well as running a slower pace but even with doing that AND getting new shoes i worry that the pain might get the best of me.



any help/advice is GREATLY appreciated.


Edited by TXNick 2010-09-27 9:39 AM