AT&T Corp said it will end its introductory offer to long distance customers of five free hours a month to its WorldNet Internet access service on March 31 and it will begin a revised hourly pricing plan. AT&T said WorldNet will continue to offer its unlimited usage pricing plan of $19.95 a month, but starting on March 31, it will offer its long distance customers that sign up for the WorldNet service and anticipate lower usage a monthly rate of $4.95 for their first five hours. Long distance customers that signed up before March 31 will continue to receive their first five hours for free for one year and they will be enrolled in the revised pricing scheme when their year ends. Customers of long distance carriers other than AT&T can receive the service for $4.95 for the first three hours. AT&T said its introductory offer brought many new users to the Internet.