Freemium games seem to be gaining more and more traction on the App Store as the days go on, with Aurora Feint today announcing that three notable game developers will be using their OpenFeint X platform to offer premium goods-based gameplay in the second half of 2010.

Private beta partnerts PikPok, RetroDreamer and Halfbrick Studios – makers of Bird Strike, Sneezies and Fruit Ninja respectively – have committed to offering free-to-play games that feature in-game virtual purchases through OpenFeint X by the end of the year.

“We’ve had tremendous success promoting our traditional games on OpenFeint and think that now is the perfect time to enter the virtual goods market,” said Jos Ruffell, Portfolio Manager of PikPok. “With OpenFeint X, we will be able to release and update content in new and interesting ways, benefiting both us and OpenFeint’s enormous player community. They really do offer a compelling partnership.”

With more than 28 million users, OpenFeint remains one of the largest social gaming platforms on the iPhone. The introduction of OpenFeint X will allow developers to offer those users in-game purchases and social gameplay experiences without the added challenge of server work.

“We’ve worked closely with OpenFeint to develop and refine the concept for our first iOS social game and are excited to launch the title with OpenFeint X support,” said Gavin Bowman of RetroDreamer, creator of hit iOS game Sneezies. “For a developer like us it would be impossible to release a social game and build the necessary server architecture without OpenFeint.”

Those wondering what OpenFeint X will look like from the consumer side won’t have to wait long. Developer HyperCube Games will be launching CorsAIR, the first OpenFeint X powered title to the App Store soon.