New York: CompuServe signed with AT&T to offer reduced-price access to the long-distance phone company's Internet customers, three weeks after rival America Online Inc. signed a similar agreement. Providers of proprietary on-line services are making major changes in their marketing strategy to adapt to intense competition from the Internet, which is cheaper. The on-line services can cut their prices because they won't be paying to connect customers to a network such as AT&T's. The companies plan to make up for the lower prices by signing up more customers, through AT&T's 90-million customer base and marketing resources. 'AT&T could be a fantastic market,' said Kevin Knott, CompuServe vice president of business development and strategic plans. 'AT&T will help us get additional exposure and more customers.'