All of the mobile image ads are keyword-targeted. You pay only when someone clicks on the ad (unlike many others that charge per impression or how many times your ad is viewed). There are four sizes of banners to choose from: (305 x 64), (215 x 34), (192 x 53), (167 x 30). The ads display the URL that they go to and the links must go to a mobile web page.
Here’s an unedited video of a chat with the developer of Google mobile ads – in true geek style. According to Google clickthrough rates for these ads are good and competition for eyeballs is lower because there is only one displayed per page.
If you have mobile web pages and want to display mobile image ads on your pages, you must update your AdSense code. Then you’ll make money each time someone clicks on a mobile ad. This might be like the beginning of the web – get in early and you’ll be ahead of everyone else. Especially in countries that are more likely to use their phones to get online than use a PC.
Mobile image ads are currently available in Australia, China, France, Germany, India, Ireland, Italy, Japan, Netherlands, Russia, Spain, the UK, and the US.
Andy’s Update: I goofed and wrote about this as well…my bad. Readers get two for the price of one today!