Hi Liz,
My thoughts are that you will not really find IPM in relation to permaculture as permaculture does not see pests as pests exactly. Sure there are a lot of references to both and it seems maybe even classes as a part of a PDC but... Generally what you will find in permaculture as it relates to IPM is more of an all inclusive habitat building scenario where eventually through sheer diversity pests are no longer a problem species because in nature with diversity also comes balance.
Even though we may not understand what job the "pests" do (except killing our beloved plants); they are doing a job and serving a function. Generally when an infestation occurs it is to remove the sick or weak. Sometimes as all things in nature can do; the pests exploit a niche that causes them to boom, which if they are eating our crops can cause much irritation!
However I believe the permaculture practice would be to use observation to see why the pests are booming. Sometimes it turns out to be our fault; to many species to close together, to much nitrogen, not enough predators and often simply not enough habitat for everything to work properly. Not enough predators is too often overlooked, most IPM tries to interrupt the life cycles of the targeted pests with no thought to the fact that you are depriving the predators of their food also. This becomes a self defeating cycle as the pests adapt eventually but the predators often do not.
It goes back to the problem is the solution, if we knew why the pests were there we could then do something about it, often it can be hard for someone to see past the pests killing their hard work to better understand what is going on. Sometimes the easiest thing to do when all options are exhausted and understanding is still not coming is to simply remove the infested plant and try again with a different variety. In that case I suppose you could say the pests are telling us to try try again.

They might also be saying hey! look here that isn't going to work.
Jeff