You are doing it! Keep doing what you are doing...exposing him to all forms of music, delighting in his enjoyment of it. An instruction setting at his age could actually cause the reverse, so I wouldnt even consider that now. Choose some children's books for him that are about composers and the history of music and musical instruments. Get him a simple native hand drum to tap, xylophone, and a music box he can wind. Use them as musical instruments, not as toys, and have good quality ones. Give them to him when you can interact and participate with him. Choose instruments that make real notes. When you play a musical CD for him, mention who the name of the composer. Mozart and Bach are excellent choices, as they offer formal structure and recurring musical themes and patterns which helps the young child in forming order, so necessary to the child. Set aside a special time during the day to listen with him, when you can both focus on the music and not on something else. Good Montessori classrooms will have integrated programs of music (as well as other forms of art) within their classrooms, the ideal way to "teach" children. You might want to look into one of them for him...usually as soon as he is porty trained. This information is shared from Momtessori...read books about it.