I always cook it down and let it cool, then freeze. I ***think*** I read somewhere that something about the thickness of pumpkin makes it iffy to can safely...at any rate, I read something about it long ago and that's why I freeze it, even though I can other things.
a quick google search says you can't can it safely...although there are recipes for canning chunks of pumpkin..you could do it that way and then cook it down when you need it.