Check out
http://www.classmateasia.com for a list of kindegarten. I sent my son to Victoria International Kindegarten in Causeway Bay - however I think they have some schools in Kowloon. They provided him with an integrated billingual programme, with both an English and Chinese teacher. The cost was around HK$3000/month. He had a lot of fun in school, but also came out learning some Chinese words as well as mastering English phonics - all before the age of 4! His teachers were caring and enthusiastic. Do check out the school.