Google has open their adsense api for the public. Using the AdSense API, you can enable users to perform a variety of AdSense functions without ever leaving your website. Users can create or manage their AdSense accounts, modify their AdSense ads, and view ad performance and earnings reports. The AdSense API is ideal for developers whose users create their own web content through web hosting, web publishing, blogging, and social networking applications.

Flexible and Functional
Using the AdSense API, you can enable users to perform a variety of AdSense functions without leaving your website, including the following:

- Create an AdSense account
- Manage an AdSense account
- Create and modify AdSense for content ad units and link units, AdSense for search boxes, and Referrals
- View detailed reports to monitor performance and earnings

Multi-Language Compatibility
To make your programming environment even easier, the AdSense API utilizes SOAP and WSDL, which support a growing number of languages - including Java, .NET, Perl, PHP, Python and XML.

This is a great oppurtunity from google adsense api to manage and develope custom ad formats and securely manage your stats. Additionally, as the developer, you can optimize your ad's placement, color, and format to increase your users' earnings–and your users don't have to do any additional work to display optimized ads.

Incase you're interested and i'm sure you are. If you want to apply for an Adsense developer API membeship you need to meet some minimum requirements such as, your site need to have a minimum of 100,000 hits, your site must register users who then maintain their web content through your site. The types of sites are eligible are web hosts, blog hosts, Wiki hosts, forum hosts, and web publishers.

Have a look at Official Adsense Announcment for Detail or you can visit the official google code site. Also if you meet the requirements why not apply for it.