China’s smartphone gaming market is starting to come of age and PapayaMobile, an Android mobile-social gaming network, is looking to capitalize on it. The company, which has offices in Beijing, Silicon Valley and London, just launched a portal for developers looking to localize their games for the Chinese market.

Android shipments in China are still small — likely around 15 million devices this year — according to conversations we’ve had with Asia-focused VCs. But China is emerging as a meaningful revenue source for many top developers. Angry Birds-maker Rovio Mobile told us China has become the company’s second-biggest market after the U.S. PopCap, which is rumored to be fielding offers above $1 billion from Electronic Arts, has also built out an aggressive (and largely independent) strategy in Asia with localized versions of titles like Plants vs. Zombies.

PapayaMobile says it can help with localization, like translating text in games, and making sure that virtual items and mechanics make sense in a cultural context there. The company will also connect developers with handset makers or carriers to secure deals for their games to come pre-installed on devices and teach them about how to market their titles.

Through this program, PapayaMobile is looking to grow its network and round up more developers for its monetization SDK, which lets developers sell in-game content and virtual goods. The company says the SDK handles local billing methods in the Chinese market, where few consumers may have credit card accounts.

PapayaMobile, which recently raised $18 million from Keytone Ventures and DCM, is a mobile-social gaming network that allows developers to layer their games with social networking features like profiles and competitive leaderboards. Unlike rivals like GREE-owned OpenFeint and Scoreloop, which was recently acquired by RIM, PapayaMobile is purely focused on Android.