Matsutake are delicious. You can get them online in october-november usually if you look around. I've gotten them from www.oregonmushrooms.com. Not cheap online; the dried version are also pretty good, but not as much.

I personally wouldn't pay ridiculous prices for them, but as I live in the SF bay area I keep an eye out when they're in season and you can usually buy them for $20 a pound or so (and a pound is a lot of mushrooms). trim off the dirt, slice them, sautee them in a little fat with onion and garlic, add in some soy sauce, white wine, maybe chicken stock, maybe strips of chicken.

The main thing with matsutake is, like truffles, they have not really been domesticated. You have to forage for them.

There's all sorts of interesting things about mushrooms- the mycelium ends up connecting multiple trees together, and they act in symbiotic relationship to each other, in terms of exchanging minerals and nutrients (which is apparently why they haven't been domesticated yet).