Hi, have you considered Kindermusic? My boy and i have been attending since he was 9mths, and from a shy baby who used to be very sensitive to sounds (he wailed loudly on the first lesson when teacher played drums!), he is now a much happier and confident 21mths toddler who dances and claps to music, and he even likes loud lion dance drumming! I attribute this to his Kindermusik classes and of cos the great teachers helped too!
The lessons are conducted mostly thru singing and dancing, with different themes for each term. The kids are also given drums, xylophones etc to play with, to expose them to different musical sounds. Its very enjoyable for both parent and child, and oh there is also a short story-telling segment at the end. Each lesson is about 45min, fees is about $30 per lesson but got to sign up for the whole term (8 weekly lessons), and also we got to buy a home kit which comprises of a CD, some reading materials, and a toy for the kid
Very fun class as a introduction to music for the very young, but for more serious music learning, that one I'm not sure... maybe seimpi?