Thanks to TonyZ, several months ago I became convinced that I needed to take a much closer look at fungi, so I put Paul Stamet's "Mycelium Running" on reserve at my local library. It just came in last week. Since then, my eyes have been opened to just a few of the possibilities.
I just found a short overview of some possibilities from a permaculture/food forest perspective here:
Mushrooms in Agroforestry