Chinese Nokia Tube users won't have access either to 3G or onboard Wifi according to Nokia's own Device Details page, meaning that there will be two separate versions of the 5800 Tube.
UK Site Gizmodo said that it might be down to the fact that China's lack of 3G network coverage could be the reason why it was disabled, which kind of not make sense as African Nokia Tube users will get 3G.
Plus China is making great strides and could become a 3G powerhouse fairly soon; Beijing has recently set a target to enroll more than 100 million mobile subscribers using homegrown 3G technology (3G TD-SCDMA) by 2011.
As for Wi-Fi, well, we can theorised that 3G and Wi-Fi were both supported by the same chip, which meant that disabling one would also affect the other. Might be due to a cost-cutting feature.
Finally, Nokia came forward with an online pseudo-emulator for the Xpressmusic 5800 which gives you an idea of how the phone - which will be released in the UK in 2009 - will work.
Interestingly, it gives you an overview of what you can expect from the phone (with some background music from Estelle's American Boy), including the soon-to-be-controversial onscreen mini SMS keyboard.