Molly Ann, That is a great idea and your class will be making a big difference to help animals.

If your going to have a large type can for pet toys/supplies the kids could give toys/grooming supplies and also supplies from home such as old towels soap ect. Would the shelter let you "follow" the story of a dog from his stay in the shelter to his forever home (of course this would have to be a dog that gets a home!) And also a lesson on what can happen if a dog/cat is not taken care of by his/her owners but is lucky enough to end up in a shelter.