AT&T Corp., as expected, said on Monday's Academy Awards telecast on ABC-TV it will debut the first spot promoting DirecTV, a satellite TV service in which AT&T invested a 2.5% equity stake (about $140 million). FCB/Leber Katz Partners, New York , handles the estimated $20 million account for AT&T. AT&T said it will begin offering the service in Hartford, Conn.; Tampa/St. Petersburg, Fla.; Dallas; and Los Angeles. Although tonight's commercials on the Oscars are national, AT&T plans to stagger the marketing of DirecTV on a state-by-state basis, said Joseph Naccio, exec-VP of AT&T consumer-small business division, in a press conference today in New York.