The natural stuff just has peanut oil - when you get it it's separated on the top and you have to stir it in. After it's stirred in good I refrigerate the peanut butter so it doesn't separate again. It's really good!
Another easy way to do natural peanut butter is to store it up side down. That way the oil is in the bottom and its easier to stir. That's for them what don't like their peanut butter cold. Just make sure the lid is on VEY tight before you do this! Voice of experience talking here.