Sharon,
Creating and maintaining a website definitely takes a level of commitment, both financially and in the area of personnel needed to manage it. That being said, it is a fantastic method for communication. Often schools spend an incredible amount of money trying to find and maintain contact with their graduates. You don't even necessarily have to start an actual 'association' if you just begin by providing a simple alumni website. A website that includes Alumni Profiles where grads can update their personal and employment info accomplishes that same thing. In fact, graduates will find YOU via a website rather than you attempting to find them.
June