Adsense API in Beta

Google have started beta tests of an API for Adsense - they've had one for adwords for quite some time. Although the beta is limited to sites with more than 100k pageviews per day with some other criteria:

To be eligible, your site must register users who then maintain their web content through your site. The types of sites we're looking for include web hosts, blog hosts, Wiki hosts, forum hosts, and web publishers.

The API site includes documentation and a signup form (via)