Google have announced a beta release of its Pay-Per-Action product for AdWords. The beta will run only in the US and roll out will take place over the next few weeks. Advertisers can list as many action types as they desire. A description for each action is provided to the publishers as well as an offer of how much they are prepared to pay for each action.
AdSense publishers will be able to opt-in to display PPA ads from Google, they also get to preview the ads, including company name, logo etc, before the ads go live.
This has long been rumored - I will be watching it closely.