Yahoo on Tuesday will take the next step to bring advertising to mobile phones by offering publishers of Web sites aimed at cellphone users a set of tools for posting and managing ads via Yahoo.

The Internet media company said it plans to offer what it calls Yahoo Mobile Publisher Services, a suite of services to place targeted advertisements in response to searches consumers perform on mobile Web browsers.

The company said beyond advertising that would run on its own Web pages, it is working with three initial partners with established mobile audiences.

The Yahoo Mobile Ad Network will include MobiTV, an early leader in delivering TV to mobile phones, Norway's Opera, whose browser is featured on many phones in Europe and Asia, and Go2, a U.S. yellow pages service for mobile phone users. The first ads will run in the second quarter.

"We started with text search on mobile phones, then we had display ads, now we have video and in-game advertising is next," said Marco Boerries, senior vice president of Yahoo's Connected Life business unit. "For the first time, mobile publishers have access to a big mobile ad network.

These services are aimed at advertisers, Web sites seeking to attract mobile phone users, as well mobile network carriers, the company said. Publishers can choose the ad formats they want to run ranging from graphical display -- or miniature banner ads -- to sponsored search links.

Sunnyvale, California-based Yahoo said it is introducing its mobile ad system in 19 countries, in a bid to convince its stable of big-name corporate advertisers that such ads will be seen by a broad-enough audience to make investment in them worthwhile.

Boerries said Yahoo plans to add more publishing partners in coming months while seeking to ensure ad quality remains high as consumers adapt to seeing more ads on their phones. More details are at http://mobile.yahoo.com/business.