Yahoo (NSDQ: YHOO) has announced its biggest carrier deal to date: America Movil, which has 143 million mobile subscribers. The deal will see oneSearch as the default mobile search engine on America Movil’s mobile portals in 16 countries across Latin America and the Caribbean. Yahoo will customize and deploy localized versions of oneSearch for each region, and America Movil may add more of Yahoo’s services over the next few months. This puts oneSearch in 19 countries around the world. (release)