We’ve said it before, but it’s worth repeating. With over a billion cell phone users, and millions more in the wing, China is a crucial market for Apple in its quest to sell more smartphones — a market it’s only been in for a few months.

But it appears to be on the right track. According to a new report from Woori Investment and Securities, Apple sold over 6 million handsets in China between January and March of this year, pushing its smartphone market share in the country up to 19%…

This is quite a feat, considering that last year Apple enjoyed a mere 8% of China’s smartphone market. But the company still has a lot of work to do if it wants to catch up to Samsung, which sells a staggering 28% of the country’s smartphones.

The dramatic rise can be attributed to the recent launch of the iPhone 4S on two of China’s larger cell phone carriers. China Unicom started offering the handset in January of this year. And China Telecom followed suit just a few months later.

Apple has yet to partner up with the country’s leading carrier, China Mobile, though we continue to hear rumors that the two companies are negotiating a deal. It seems that incompatible network technology is still a major roadblock.

That could all change, however, with Apple’s next smartphone. The company is rumored to be using a new Qualcomm chip in the handset that will be compatible with China Mobile’s TD-SCDMA network, giving it access to more than 600 million wireless customers. Wow.

We’ll certainly be keeping an eye on China’s smartphone market over the next several months, as it’s quickly becoming a battleground for mobile platforms. Google is winning it. Apple wants to win it. And Microsoft thinks it’s winning it.

[TheNextWeb]