Japanese wireless operator KDDI is planning to launch service in the U.S. The company will lease Sprint's network to offer its service to Japanese residents of the U.S., and later offer prepaid services for visiting tourists, according to a Japanese newspaper report.

KDDI is perhaps best known for its massively popular full-song download service in Japan, which has sold more than 100 million songs since launch in 2004. The U.S. version of the KDDI service won't immediately offer the same service, but plans to include songs, ringtones and social networking services will be added over time, according to the article.