MOTT's apple juice all the way! Both the "natural" kind that is kind of opaque and the regular kind that just says "100% juice" and is translucent are gluten free. My cousin who is a five year old autistic celiac, as well as my girlfriend who is an extremely sensative celiac have always been fine with Mott's! I know that my cousin also eats several of the Mott's brand apple sauces. I think a few of the apple sauces are off limits to because he cannot have soy either - but a few may have gluten, I'm not sure. The apple juice is definately fine though!
Other brands that I have seen listed as gluten free but have not tested are: Del Monte (all juices), Dole (all juices), Lucky Leaf apple juice and apply cider & sparkling apple cider, minute maid (all juices), musselman's, ocean spray 100% apple juice and safeway supermarket brand apple juice.
Hope that helps!

*i wish I could get a college degree in gluten-free foods!*