I could write a book on this.
I'm a registered Suzuki violin teacher, and I love the method. It's based on a philosophy that every child can learn to play a musical instrument, just like every child can learn to speak. One of the important philosophies is that a child learns best ina loving, positive enviroment, and lesson concepts are broken down into tiny teaching points that are mastered one by one. It's also incredibly parent friendly if you find the right teacher- you don't have to have any musical instrument experience to help your child be sucessful. I respectfully disagree that a parent should start lessons before the child- I really haven't found it necessary; but a parent does have to be very involved in practicing, lessons, acitvities, etc. My best advice if you decide to go that route, is to observe a lot of teachers if possible before comitting to one, so you find one whose personality and style fit with you and your child.
I teach several children inthe 3-4 year old range and it's wonderfully sucessful. Just like learning a second language is easy as a young child, so is learning an instrument. I love watching my little ones discover and learn- they don't know that playing the violin is supposed to be hard, and they get so excited by their progress. My almost five year old is also doing Suzuki Violin with a different teacher and it's done wonderful things for her.
We have also had terrific experience with Music Together. I can't say enough good about that. My kids still listen to and sing the songs all the time, even though we haven't been to the classes in a year or so. I also founda range of "crunchy parents" there. My two year old would frequently nurse during class and she wasn't the oldest nursling!
Good luck in your journey, and pm if you have more questions. I'm always happy to talk someone's ear off about Suzuki.