ON AND OFF THE AIR:
* Barbara Walters has an extended interview on ABC's "20/20" tonight with Terry Waite, the Anglican church negotiator who was held hostage in Lebanon for five years before his release last fall (at 10 p.m., Channel 13).
The former prisoner discloses that at one point during his captivity he believed he might have been able to escape. But doing so could have meant shooting one of his guards, and he did not want to violate his pacifist beliefs.
Waite also says he endured torture, a mock execution and four years in solitary confinement, and was apparently kidnapped because his captors believed he was spying for the U.S. government in seeking a release of all hostages.
* It is hard to view anyone spending $20 million on his racing effort as a poor underdog. But skipper Dennis Connor is an underdog nonetheless in this weekend's resumption of America's Cup racing off San Diego.
The ESPN cable network's splendid live coverage of the defender and challenger finals resumes at 3 p.m. tomorrow and continues through next week.
Connor's Stars and Stripes is up against the $60 million America3 ("America cubed") syndicate of Bill Koch, which went into this year's yachting event with four boats that have been narrowed to two.
And as commentators Jim Kelly, Gary Jobson and Peter Isler have noted, the Koch group has spent an estimated $60 million on their effort. In relative terms, therefore, one-boat Connor is the underdog.
And have you noticed the unprecedented, prominent commercialism of the Connor effort? His sails flaunt advertising for Pepsi, Citizen watches and Cadillac, and his crew members wear jackets with American Airlines logos.
* The scheduled airing of a youth-oriented weekend special aimed at stimulating black students to stay in school was inadvertently misstated in this space yesterday.
"Success Through Education: A Salute to Black Achievement," is actually scheduled at 7 p.m. Sunday (not Saturday) on WJZ-Channel 13. Rap stars Heavy D and MC Lyte, and actress Kellie Williams ("Family Matters") talk to Baltimore young people in a show taped on location at City College.
* So where in the world would William Shatner, best known as Capt. James T. Kirk of the "Star Trek" series, choose to vacation? It's Barcelona, Spain during the Olympic Summer Games, he reveals on "The Rich and Famous 1992 World's Best" special at 1 p.m. Sunday on Channel 13.
Also featured are Ivana Trump, Regis Philbin, MTV personality Julie Brown and actor Peter Weller.