Yahoo! ( YHOO) and BellSouth ( BLS) agreed to jointly sell high-speed Internet service starting next year. Yahoo! and BellSouth will market the offering on the Yahoo! site and in BellSouth's advertising, the companies said in a statement. BellSouth currently has 2.4 million high-speed Net customers in nine states. The Yahoo! features will be available to customers for free. The alliance is the latest that Sunnyvale, Calif.-based Yahoo! has formed with telecom providers. It already has deals with Verizon ( VZ) and SBC Communications ( SBC). Last week, it extended its partnership with BT Group's ( BT) British Telecommunications unit. Demand for high-speed Internet services is increasing at a faster rate than traditional phone services, which is spurring Atlanta-based BellSouth and other telecommunications outfits to compete for these customers. "Yahoo! is a weapon that helps them in that battle," said Martin Pyykkonen, an analyst with Hoefer & Arnett who rates Yahoo! shares strong buy and doesn't own them. He doesn't rate BellSouth. "From Yahoo!'s standpoint, there really is minimal costs." Yahoo!, which is slated to report third-quarter earnings tomorrow, declined to release financial details. The company continues to pursue similar agreements, said Jim Schinella, a vice president for business development at Yahoo!, in an interview. Shares of Yahoo! rose 61 cents to $34.13 while BellSouth rose 3 cents to $25.06.