In a bid to outshine Google in the mobile space, Yahoo is announcing a new Web ad network initiative today for cell phones. This lets marketers place ads simultaneously within Yahoo's mobile services as well as on pages by other publishers.

The new ad network is part of an initiative that contains new Yahoo! mobile applications, as well as integration with its current array of publishers: MobiTV (which streams video to cell phones), Opera (a company that makes a mobile Web browser), and Go2 (a yellow pages site).

Yahoo now joins mobile ad companies such as Third Screen Media and AdMob in the small, but rapidly expanding, market for mobile advertising.

Yahoo to Offer a Network for Web Ads on Cellphones [NYT]