I have eaten some porcupines. It is difficult to just pick up a porcupine in the woods due to the quills, so be prepared to hog tie and carry off to the side of your body or throw in a tarp and carry (again off to the side of your body because some quills will cut through the tarp). Edit: having a friend to carry helps. Holding a hog tied dead porcupine and carrying it for 3 miles is difficult. Not that I would know or anything!
Are you asking how to skin the porcupine? I could explain that if needed. Short version (heavy gloves are recommended): The first step is cutting off the hands, feet, and head while the porcupine is sitting face up -- usually with a big butcher knife. This is done on a piece of plywood or large cutting board. Then you skin and gut by tying the porcupine up on a rack of some sort, neck down and belly facing out. The rope to tie goes through the pubic bone which you
should expose before you rack the porcupine up. On a rack of some sort that allows the porcupine to freely hang: with meat scissors or a sharp knife you then open and pull the skin off the meat and doing your best to cut at the fascia/skin and not the meat -- using your bare hands if necessary. Separate the guts from the carcass (don't hit the gall bladder!!!) and throw in a
bucket to bury later. Keep them away from your dogs!
Once the hide is off I would throw it in a bucket and deal with it the next day. Allowing some level of rot will allow the quills to come out easier. If you're wanting the quills you just pull them out with pliers. They are tenacious things, so be careful. Again, wear heavy gloves. I would then dry them over a fire of some sort. Hancock House has a book on quillwork that you could check out if you wanted.
http://www.hancockhouse.com/products/indqui.htm
You could also search "Skinning a Raccoon" for more thorough instructions.
Once you have skinned the porcupine: I would hang the carcass for three days as the meat is really tough and hanging it allows it to rest and taste much better. Hang inside your house wrapped in an old sheet.
Porcupine, like raccoon, tastes like dark meat
chicken. But it's super tough. I would cook cuts of the porcupine in a slow cooker with lots of poultry type spices. Do not
oven cook or bbq it as it won't come out right (dry and tough). I think old Joy of Cooking cookbooks have recipes for raccoon too.