Wired has a really interesting story on iPhones in China discussing how readily available they are now and how popular they've become. I know about the black market versions (ie most likely fakes) and when in Shenzhen I saw a few authorized Apple dealers that had unlocked iPhones in stock (this is not to say they don't exist in Beijing, I just haven't been shopping here that much). However, I've yet to come across anyone using an iPhone in China. My feeling is that Wired overstates the trend.
The number of authorized Apple dealers has certainly skyrocketed over the past few years and genuine Apple products are fairly easy to find, however the price still prevents many Chinese from purchasing them. In Shenzhen, where free wireless is abundant, it was common to see a number of foreigners using Apple, but you'd rarely see Chinese using them. Also, on the subway, foreigners seemed to be the sole users of iPods. In my short time in Beijing, I've noticed a number of Chinese iPod users, but that's about it. And when it comes to computer usage in China, it seems like there is only one choice for business people, Lenovo/IBM.
Apple definitely has room, and potential, to grow in China, but I think its still far from that point. Like in the US, I believe the cheaper, cool items like the iPod and iPhone will serve as a gateway, people will get hooked and then end up buying the computers, like in the US. The Wired story captures the iPhone/Apple popularity in China, but it is discussing a basically non-existent trend, though its easy to imagine that iPods and iPhones will be as ubiquitous in China could come close to matching the US if given more time.