Google has not yet announced this but there is now an official Google AdSense app in the Apple iTunes Store by Google for free.
The AdSense app provides an easy way to access key data from your AdSense account. Access reporting features anywhere, directly from your iPhone. The first version of the app gives you access to: the key earnings information, top custom and URL channels, ad units and sites reports, payment alerts.
Requirements: Compatible with iPhone 3GS, iPhone 4, iPhone 4S, iPhone 5, iPod touch (3rd generation), iPod touch (4th generation), iPod touch (5th generation) and iPad. Requires iOS 6.0 or later. This app is optimized for iPhone 5
Here are screen shots of the app: