Google has released an official AdSense app, so users can now conveniently check their ad-based earnings and other pertinent AdSense data. The app is somewhat limited to the extent that users can't make any fundamental changes to their account via the mobile app.
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.
While Google notes that the app is optimized for the iPhone 5, it will work on devices as old as the iPhone 3GS. Note, though, that the app requires iOS 6 or later. As one would expect from Google, the app is free.