Thank you to MMario, Yarnguy716, and Tallguy for all of the information and tips on using butternut hulls to dye yarn. I, of course, couldn't wait on the wool I ordered to arrive to try this. Instead I had about 3/4 of a skein of Paton's Classic Wool Merino in Aran color laying around and decided to have a go with it. Here is the result. One picture is with a flash and one is without because both reflect the color of the yarn depending on the way you look at it. I LOVE it!
Also, I put what I did on my blog if you are interested. Here are the links.