Market Street Music is one of the premier Kindermusik studios in the nation. I have had my 5-year-old daughter in their classes since she was 6-months old, and she is well on her way to reading music and can carry a tune with the best of them.
My 2-year-old son has been enrolled from about 9-months old and asks almost every single day for his music class teacher, whom he just adores.
The Kindermusik curriculum itself is fantastic, but it's the teachers at Market Street, particularly Katie & Denise, who make the experience so fantastic for the kids.
You can take a trial class for free, and I would recommend trying them out first. Be warned that it *is* a little pricey, but in my opinion, worth every penny.