T-Mobile USA today said it’s adding Yahoo!’s oneSearch, customizable home pages and a new shopping store to its smartphones and feature phones alike.

The changes coincide with decreased corporate earnings, the expansion of T-Mobile’s 3G network and a variety of increased data plan rates as announced last month.

Yahoo!’s service returns mobile-specific data, not just typical Web results. For example, a sports team search would return scores, schedules, a roster, news and images, while a movie search would return local show times, reviews and casting information, the company explained. Searches also look for any relevant T-Mobile data such as appropriate ring tones and wallpapers. Yahoo! also partners with T-Mobile overseas.

T-Mobile refers to the overall software update as web2go and said it is automatically available starting today. Yahoo! and T-Mobile plan to share ad revenue, but no details were disclosed.

In the United States, Yahoo! is also working with AT&T for its search and advertising while Google partners with Sprint. Still up in the air is Verizon Wireless, which is currently being wooed by Google and Microsoft.