Google have today announced that their AdSense for Mobile Applications program has now entered a public beta phase.
AdSense for Mobile Applications allows mobile app developers to display text and image advertisements from the Google Adsense network directly in their apps.

The program is currently only open for developers of free iPhone or Android applications that generate in excess of 100,000 pageviews each day.
Google have been testing the system for a few months now with a small number of hand-picked partners (you may have noticed ads in the Shazam Android app), and have now decided to make the program available to more developers.
“In order to continue growing the mobile application market, developers need to make money to fund their projects,” Google said in a statement. “We hope AdSense for Mobile Applications will encourage iPhone and Android developers to keep making new, innovative mobile applications.”
[via googlemobile.blogspot.com]