The iPhone was initially available only in the U.S., United Kingdom and parts of Europe. Now the ubiquitous touch-screen smartphone is around the world. While many countries are untapped markets for the popular device, one stands out.

China.

Now Apple (Nasdaq: AAPL) has made a three-year deal with China’s second-largest mobile phone carrier. With the addition of China, the iPhone is now available in a market larger than the U.S. and European Union combined. China already has more wireless subscribers than there are people in either the U.S. or EU — and that’s true even though half of China’s population doesn’t use them.

While the benefits to Apple are good, the benefits to its partner are even better. Unlike other deals Apple has made with wireless providers, its Chinese operator will not share revenue. Instead, the Chinese company gets all of it. It will simply buy iPhones wholesale and resell them to its customers. It gets 100% of the service revenue and 100% of the profit from the retail sale of the phone.

While pricing hasn’t yet been released, the company already has more than 140 million wireless users, about 20% of the total market. The company expects that the addition of the iPhone will attract not only more customers, but also high-spending customers, which will boost earnings.

China Unicom (NYSE: CHU) has a market cap of $34 billion. CHU also pays a small dividend that amounts to a 2.2% yield at recent prices. (Apple paid its last dividend in 1995). CHU is also more attractively priced. Its forward P/E is 19.7, compared with AAPL’s 28.9.

If you want to get a chance to profit from the massive potential the iPhone has in China, forget Apple. China Unicom is the better investment by far.