running_scared - 7:59 am on Sep 25, 2007 (gmt 0)

From Inside AdWords:

We've heard your requests for a cost-per-acquisition (CPA) bidding tool so we're excited to introduce a new AdWords feature: the Conversion Optimizer beta. Conversion Optimizer helps you meet your ROI objectives by automatically managing your bids according to a maximum CPA goal. By automating the bidding process, this feature helps you minimize your conversion costs while saving you time.

FAQ - [adwords.google.com...]