Just like the iPhone, Nokia 5800 XpressMusic 'Tube' won't have 3G or Wi-Fi enabled when it makes its way to China, which pretty much negates any reasons that customers might have to want one. The 3G exclusion can at least be blamed on China's lack of coverage, but disabling Wi-Fi on every new phone just doesn't make sense. All China's regular internet traffic is filtered anyway, so regulators either have a crucial misunderstanding of what Wi-Fi is or a serious problem with people enjoying things. [Nokia - Thanks, Lauri!]
It's not about censorship, it's about promoting TD-SCDMA (the Chinese 3G standard, which frankly needs all the help it can get). They've invested so much money in the standard that they really hate anything that would draw people away from it; it's also the reason they still haven't allowed operators to launch 3G services that use international standards. About 18 months or so ago one of the bureaucratic bigwigs implied that there was a good chance the government would allow TD-SCDMA phones to have WiFi functions, but not GSM or the other 3G standards.
And yes, it's the regulator's decision, not Nokia or the networks; you'll find the same thing with handsets from HTC etc. To legally sell mobile handsets in China the model has to have been given a Network Access Certificate, which they have never given to a phone with WiFi functions.
It's all a big sham because there's zero enforcement against people who sell knock-offs or grey market' handsets imported from HK or wherever that have all their functions intact. So really the only people it hurts are the big foreign companies like Nokia who can't get involved in anything illegal.
(I work in the telecom industry here and I'm bitter, can you tell....?)