You'll remember that the iPhone didn't hit the Chinese market until 2009, a full two years after the U.S. launch. In that time, a hugely disruptive gray market emerged and continues to operate.
Since then, the delay between U.S. and China product releases has shortened. The iPad and iPhone 4 became available in China just six months after their respective U.S. release, and Apple intends to sell the MacBook Air in November, just about a month after hit shelves in America.
Apple products are becoming more popular in China, despite that fact that they still represent a niche market (Apple holds just 5.9 precent of the Chinese smartphone market share, for example). Of course, these delays aren't entirely on Apple's shoulders, as all electronic devices sold in China must first receive the approval of several governing bodies.