@Biscuet & Reid
I think Go Tone subscribers are able to use iPhone data - I spoke with a woman on the subway who said that she bought an iPhone in the US and was using it on post-paid Go Tone service.
By the way, if you're lost, you should check out the HoodHot Beijing Taxi Guide App on the iTunes App Store, it'll show the taxi driver the Chinese addresses to over 1000 places in Beijing. Check it out at www.HoodHotTravel.com