"Stronger ears," being able to identify musical sounds better, will help almost any music student. But ear training is difficult to teach in a classroom, because it works best with personalized instruction. Other ear training programs focus on delivering drills and quizzes to students, which can be frustrating and difficult.
After seeing even college-level students struggle with ear training, I created Sebastian (http://playsebastian.com). Sebastian starts with very simple interval identification problems, gradually increasing in difficulty as the student improves. Problems are generated randomly using constraints that carefully model the student's ability level. There is no drill or quiz---just a seamless flow of learning that feels like a game, without the sugar of many educational games. The interface is simple enough that any age student can use it.
The demo is free and covers a variety of interval problem types. If you want to use Sebastian in an educational setting and are interested in trying the full version, send me an email (firstname.lastname@example.org).