A large advertising marketplace for the Web is getting into mobile in a bigger way. Adknowledge, billed as the fourth largest online ad marketplace, is offering an SDK for Android developers to integrate ads with their games.

Adknowledge acquired Super Rewards through its acquisition of KITN Media in 2009. Today, Adknowledge’s Super Rewards announced its venture into the mobile ecosystem with the release of the Android SDK. The SDK gives consumers the ability to acquire virtual currency in multiple ways.

Chris Smutny, general manager of Virtual Currency and Gaming at Adknowledge, says the free-to-play, or F2P, model is quickly proving itself to be the preeminent way to monetize games. He believes mobile game developers will adopt the free-to-play model in a huge way in 2011, and “this product provides them a very easy way to handle all the monetization and customer service issues.”

Smutny says Adknowledge’s Super Rewards has worked with thousands of casual games publishers over the past three years and taken all that knowledge and adjusted it for mobile. “We want to provide consumers the choice to pay in the way that’s most natural to them,” whether that be Pay Pal, direct to a mobile phone bill, a credit card or something else.

So, why launch on Android first? Smutny says a similar release will come for iOS, but points out that in the third quarter of last year, Android represented 26 percent of new smartphone sales, according to Gartner. Plus – and this is a big one – Android is an open platform, and “at the core, we believe an open platform pushes forward innovation at a very rapid rate.”

The Android mobile SDK works on the most popular Android devices running OS 1.6+ and uses the same optimization algorithms as the company’s Web-based platform, which means only the most relevant offers, or those most likely to result in conversions, will be shown to users.