I picked this movie up late last week and watched it over the weekend. I recommend it as a demo disk. The sound mix was great and it will really works your sub also. If I am not mistaken, Skywalker Sound was mentioned in the credits. Don't hold me to that though. Of course Pixar did a great job on the animation side of it too.
Did it win any awards for sound or sound editing? If it did not, it should have.