Google on Thursday said it has begun beta-testing its widely anticipated radio advertising system with a small group of AdWords advertisers, reports Reuters.

In a statement on its official AdWords blog, Google said it had completed the integration of the system acquired via Google's acquisition of dMarc Broadcasting in early 2006, and test ads have already aired but Google hasn't yet determined when the system will be more widely released.

"Google Audio Ads brings efficiency, accountability, and enhanced ROI to radio advertising by providing advertisers with an online interface for creating and launching radio campaigns. You'll be able to target your customers by location, station type, day of the week, and time of day. After the radio ads are run, you will be able to view online reports that tell you exactly when your ad played," Google said.

ZDNet blogger Donna Bogatin, in an earlier post, offers some pics of how Google Radio Audio Ads will be served.