WORTH NOTING ON TV

FRIDAY

Great Performances (PBS, 9-10:30 p.m.): Portraits of two potent musical stars emerge in "Kathleen Battle and Wynton Marsalis: Baroque Duet," one of several shows PBS is airing throughout February to celebrate Black History Month. In a mix of new material and background footage, opera-star Battle and jazz-classical trumpeter Marsalis perform Handel and Bach for the program, and each is shown in other moments - public and personal.

SUNDAY

Kindergarten Cop (NBC, 8:30-11 p.m.): The 1990 comedy film having its TV debut here may be mainly for Arnold Schwarzenegger watchers, but it does offer the peculiar spectacle of the muscular star trying to teach a class of anarchic tots in Oregon. He's an underground drug agent, and it's all part of his plan to track down a killer. Amid the fun, the plot delivers some timely messages against drug abuse and domestic violence.

TUESDAY

Class Clowns (ABC, 10-11 p.m.): It's one thing for parents and politicians to tell kids they must finish high school. It's quite another when the advice comes from the likes of Bill Cosby, Burt Reynolds, or Roseanne Arnold. In this special, Cosby goes to Philadelphia's Central High to pick up, finally, his diploma and to plug the value of attending class - in the process delivering a monologue about his former algebra teacher. Roseanne and Tom Arnold crack jokes with students at Westview High School in L os Angeles and also stress the need to stay in school. Other stars do the same elsewhere - dispensing sound advice in a distinctly unpreachy style.Please check local listings for all programs, especially those on PBS.