If China Unicom (CHU) is the AT&T of China, having enjoyed an 18-month monopoly as Apple’s (AAPL) only official iPhone carrier in the world’s largest mobile phone market, then China Telecom (CHA) just became its Verizon.

The carrier began taking orders for the iPhone 4S a week ago, and by the time doors opened Friday at China Telecom’s 2,850 retail outlets, pre-sales had reportedly passed 200,000.

It may be the country’s No. 3 mobile operator (total subscribers: 216 million), but China Telecom has the largest Wi-Fi network (30,000 hot spots) and 38.7 million 3G subscribers — nearly as many as China Unicom’s 43 million.

China Mobile (CHL), the country’s largest carrier (600 million subscribers) has been talking to Apple for years and is expected to start selling the iPhone when an LTE version arrives, probably later this year. Meanwhile, so eager are its customers to get their hands on Apple’s pocket computer that more than 15 million are using gray market iPhones on China Mobile’s sluggish 2G network.

China has caught Apple fever, as the massive crowds that gathered for January’s iPhone 4S launch made clear. Morgan Stanley’s Katy Huberty estimates that when the device is available from all three mobile carriers, sales in the country will quickly reach 40 million a year. See here.

To put that number in context, Apple’s worldwide iPhone sales in fiscal 2011 were 72.3 million.