I've got about 3oz of cascade hops that spent 2 years in the freezer before I decided around January 2011 to take them out, put them in a paper bag, and let them sit at room temperature to age so I can brew a lambic. Over the course of the last several months, anytime I opened the closet that I was storing them in I would get smacked in the face with a cheesy aroma. However, a couple of weeks ago, I realized that I couldn't smell the cheese anymore, and today I finally opened the bag up, stirred my hand around in it, and stuck my nose in and inhaled, and no noticeable cheese aroma. Is this a useful indicator that they are aged enough to put into a Lambic without causing off flavors or excess bitterness?
Try chewing a small leaf, or making hop tea with a couple of cones. This will help you gauge how much bitterness and aroma is left.