AT&T Inc., the largest provider of telephone services in the United States, has become the nation’s first carrier that features Yahoo Inc.'s OneSearch Web search engine on its cellular phones, both companies announced on Monday.

Until the deal with Yahoo, AT& T’s cell phones were providing users with a search function from Infospace Inc. on the carrier's MEdia Net cell phone portal. Yahoo’s OneSearch joins the gaps of the search engine into one application.

Yahoo Inc. will also provide the advertising that comes with the search results. The two giant companies struck the deal in January. Under that deal, Yahoo became AT&T’s search provider for TV, mobile, and Internet services.

The Santa Clara, California-based company is already providing OneSearch to about 60 overseas carriers. Yahoo is the exclusive cell phone search provider in Europe for T-Mobile and Deutsche Telekom.

AT&T said it wants to offer through its Internet portal to its customers Yahoo’s mobile Web services such as links to news, financial information, weather, Flickr photos and others.

Also under the new agreement, AT&T's YellowPages.com will provide local search data.

Yahoo is also currently in talks with Verizon Communications Inc to provide the broadband and telecommunications company Web services on its broadband and TV. The agreement does not cover cell phones and Verizon is currently in talks with Google Inc to become the Web search provider for Verizon Wireless mobile phone customers.