With yesterday’s announcement that Apple is launching an in-game digital goods transaction platform this summer, iPhone developers are now evaluating increasing monetization options for their apps and social games.

Direct Digital Goods Sales

While developers have been hacking their way to in-game purchases already – primarily through the form of buying paid versions of the same game that come with differing amounts of virtual currency – Apple’s new “In-App Purchase” platform will make buying levels, add-ons, currency, and other content easier than ever. Users must only approve a purchase prompt and the bill goes directly to their iTunes account; meanwhile, developers keep 70% of the total purchase price.

This is great news for developers large and small alike. Top iPhone social game developers like SGN and Zynga have been developing user pay models from the beginning and should be well positioned to take advantage of the new payment APIs. (Apple still doesn’t currently allow other payment services to be integrated in iPhone apps.)

However, developers are already increasingly exploring additional monetization models to maximize app revenues.

Incentivized Virtual Currency

One such model that has proven quite successful on social networks like Facebook and MySpace is incentivized virtual currency. Super Rewards and Offerpal Media, two of the leaders in the space, have recently launched similar programs for iPhone app developers. The user experience is somewhat similar: inside the game, players can choose to participate in a variety of free offers; when they do, the advertiser reports it back and (usually within 15 minutes) the player is credited with virtual currency in the game. At left, you can see what a sample offer looks like in the iPhone game Loot Wars from Super Rewards.

It’s still early, but we expect incentivized virtual currency to become a very powerful way for developers to monetize their the iPhone apps.

Mobile Advertising

Developers are also increasingly using mobile advertising networks that specialize in delivering inventory targeted by geography and device. Mobile ad networks like AdMob and Greystripe have recently been increasing their focus on iPhone app and game developers specifically, given the explosion in app use.

Recently, AdMob told Inside Social Games that it now has 800 iPhone apps in its network, primarily in games and entertainment. AdMob’s Mike Fyall said games is currently one of the higest performing categories in terms of CPA ads leading players to download other apps.

“A lot of people are driving traffic to free apps, then upselling the paid apps,” Fyall says. “Ads perform well at natural transition points, like right after players have found what they’re looking for.”

Greystripe has also launched rich media Flash ads for iPhone apps.

Conclusion

While social game developers on the iPhone have always reported fantastic engagement levels, the number of ways developers are able to monetize that engagement is only increasing. With all of the opportunities for integration with friends through Facebook Connect for the iPhone, it’s never been a more exciting time to be building social games on the iPhone.