I found it at Amazon, and I've been liking it a lot. Or try a search for 'pink butcher paper' (not sure why it's pink, but there you go). Just make sure it's not the waterproof kind of butcher paper, and that it's not the stuff that crafters and schoolkids use for making murals. You want something 'food grade' .
Here's the stuff I use, and the tube is a nice way to store it.
http://www.amazon.com/Pink-Butcher-Paper-Durable-Carry/dp/B00NC5S6OM/ref=sr_1_2?s=home-garden&ie=UTF8&qid=1436316013&sr=1-2&keywords=butcher+paperThe basic idea is that you smoke something until it's got some nice bark, at which point you wrap it in the paper to retain some of the moisture for the rest of the cook while also not steaming the meat (as you would with a foil wrap). It's kind of a compromise between going naked and foiling.
I started wrapping my ribs this way, and it seems to have helped them stay more tender. It's also a great medium for reheating-- I just leave them wrapped in the juicy paper and microwave them like that. I also used it on a recent brisket, but I'm such a newB at brisket that I should refrain from comment. I still do my butts naked.