My younger son attends TweedleWink where they use tuning forks to teach them the sound of each note. The children also get to feel the vibrations from the tuning forks. In addition to that, they are also taught to read music with flashcards, e.g. this is "C" (shows middle C on the stave), this is C on the piano (shows the position of C on a keyboard. They also play the sound of "C" for the children to listen. Then they are exposed to excerpts from famous classical pieces. Finally, they beat wooden sticks together to follow a rhythm pattern.
The other thing I do is play music for them when they are playing, when we're in the car. I play all sorts of stuff - songs, classical music, contemporary.
Lately, I've been wanting to send my older son (turning 4 this month) for music lessons. My past attempts have been unsuccessful. I tried Kindermusik and the Yamaha program - both of which are more like music appreciation really. I was considering sending my older son for Suzuki but I had to drop the idea because I couldn't commit to the schedule from the one and only teacher I could find who was a certified Suzuki teacher teaching the piano. I didn't want to invest in a violin because I wasn't sure if my older son would take to it. We have a piano at home already so that didn't require such a hefty investment.
Since I had to drop the Suzuki idea, I decided to get the Piano Wizard Music Academy program. My older son loves playing the Nintendo Wii - I used to play the Wii Fit for exercise and that's how he got hooked - so I figured a program like the Piano Wizard Music Academy would work well for him.
I have the book Nurtured by Love which talks about the concept of talent education. It breaks away from the idea that a child is either born with musical talent or isn't. Suzuki believed that talent is taught and that if a child appears incapable of learning how to play an instrument then the problem lies in the teaching method, not with the child's "inability". His premise for his theory is based on the fact that most child learn to speak their native languages and they learn how to speak it fluently. Although most people take that for granted, Suzuki felt it was an amazing achievement. And if children can learn something as complex as language, then why not music? I haven't finished reading the book, but I don't think it is a "how to" book, it is more of a "why" book. Still interesting reading, but if you want a book to help you teach your child music through the Suzuki method, I don't think this is the book to get. I searched Amazon for Suzuki Music books and found the following list:
http://www.figur8.net/resources/music/I only have Nurtured by Love so I don't know much about the other books. My plan is to start with Piano Wizard to get my son interested in playing the piano and then shift to more formal lessons after that.