My suggestion is the Suzuki method. She would learn to play by memorizing the songs starting with Twinkle, Twinkle, since she is probably too young to learn how the read the music yet. You can buy the books on amazon.com, young-musicians.com or sharmusic.com. You can get just the book or the book with a CD if you want to spend the extra money. I was in a Suzuki class myself with kids as young as she is, all the way up to high school.