Edward Klein, editor of The New York Times Magazine for 10 years, has resigned, the paper announced yesterday. Klein informed his staff of his decision at a Friday afternoon gathering in his office, at which he said he was leaving the paper to pursue "different challenges." Though some colleagues found Klein sometimes abrasive, his staff was moved by a "poignant" resignation speech in which he thanked them for their good work, according to one magazine staffer.

Rumors of Klein's imminent departure have been circulating in New York for months, following recent publication in the magazine of two stories of questionable accuracy, and at least two publications that regularly twit The Times -- Spy and The Village Voice -- have been speculating about successors. Times Executive Editor Max Frankel is expected to name Klein's replacement within a week or two. The Times has traditionally promoted from within.

"It's always sad when something like this happens," the magazine staffer commented, "but {Klein} handled it very well."

In July, the magazine ran a staged, four-year-old photo and misidentified it as a recent Miami drug arrest. And a week earlier, the newspaper had run an editor's note clarifying the status of writer Rae Lawrence, whose story in the magazine about trying to get her novel published left the mistaken impression she had no previous literary experience.

Klein left Newsweek in 1977 to take the Times job. In 1982, the magazine published Nan Robertson's Pulitzer Prize-winning account of her battle with toxic shock syndrome.

Klein told his staff he has no new job lined up, but there is a big event in his future: He is getting remarried next week.

Reagan's Call

As his wife Nancy recuperated from breast cancer surgery Saturday, President Reagan took the time to give the Nagy family in Evans City, Pa., the thrill of a lifetime. He called personally to decline a dinner invitation Sheila Nagy had sent the Reagans in early September.

Nagy wrote to thank the president for improving the economy and invited him to enjoy dinner with her "normal American family."

When she picked up the phone about 4:30, the operator asked her to hold for the president. She was so startled she asked, "The president of what?" Reagan also chatted with Nagy's husband Lewis, a truck driver, and three of their five children. "I couldn't believe I was so relaxed," she said later. The conversation "was like talking to the neighbor next door."

Myerson: Koch Not to Blame

Former Miss America Bess Myerson can also see beyond the gloom of her present problems, which are of quite a different sort. In an interview published yesterday in Newsday, Myerson said she holds no grudge against New York Mayor Edward Koch, who has not rushed to her support in the midst of a scandal involving a now-retired state judge.

Myerson and her frequent companion, Carl Capasso, have been charged with trying to influence former state judge Hortense Gabel into granting favorable terms for Capasso's divorce. Both have pleaded not guilty. Myerson, 63, had played an important role in Koch's 1977 election, but now she doesn't blame him for turning his back on her. "That is a decision he has to make," she said. "I don't hold him to blame in any way."

Michael Jackson's Advice

Michael Jackson is apparently so pleased with his own physical transformation he's recommending plastic surgery to his mother. Katherine Jackson told Us magazine her famous son helps her choose her clothes, advises her to wear lipstick when company visits and encourages her to lose weight. "He said, 'Elizabeth {Taylor} lost all that weight. If she has, you can. And if you don't like it you can always have plastic surgery.' "

Katherine Jackson added, however, that she doesn't want plastic surgery and doesn't understand why Michael had a nose job and a cleft put in his chin.

-- Compiled from press and wire reports by Sarah Peasley