I just found out they're putting xylitol in some fancy brands of peanut butter. Xylitol is deadly to dogs even in rather small amounts, so read the labels. I don't remember if I used Skippy or Jif or Peter Pan, but I did check the label and it just has plain old sugar and is safe. (I wish they didn't put any sweeteners in PB, I have to make my own if I want the good stuff)
You can buy unsweetened PB. It's what we have in my house. This one, in fact. It's probably available everywhere.