By Belinda Luscombe

NOW, JUST WHAT CAN GOLDIE BE UP, UP AND UP TO?

More is known about the identity of the Unabomber than about WOODY ALLEN'S movies before they're done. But word on the film he's shooting now is that it may be a musical (he hasn't made up his mind); it's set in Paris, Venice and New York City; and he has punched up the pulchritude level, casting Julia Roberts, Drew Barrymore and a re-emergent GOLDIE HAWN (getting a leg up in Paris) rather than more cerebral regulars Judy Davis or Dianne Wiest. "This is different from anything Woody has done before," says producer Jean Doumanian. "Goldie and Woody were magical together." With strings attached, of course. IF IT'S DI, IT'S BYE-BYE

Is it a truth universally acknowledged that any man who's just friends with PRINCESS DI is believed to be leaving his wife? A case in point is British rugby team captain WILL CARLING. Tabloid reports surfaced in the summer that Carling had indulged in some extracurricular scrimmaging with Di, whom he met at a gym. In August, however, Carling said he intended to stick by Julia, his wife of 14 months. "She picked the wrong couple to do it with this time," Mrs. Carling said, "because we can only get stronger from it." Well, not exactly. The Rugby Union announced on Friday that the Carlings were separating, adding, somewhat implausibly, that "no one else was involved." SEEN & HEARD

Arthur Miller is turning 80, and he's celebrating among loved ones: Britons. He had a New York party, but his real birthday (Oct. 17) will be spent at the Arthur Miller Center for American Studies in Norwich, England. Age has not wearied Miller, who still writes. "It's the same job it always was," he says.

Don't discount the possibility of little Newts. In a friendly chat with Arianna Huffington in November's Ladies' Home Journal, Marianne Gingrich says the two "haven't ruled it out." Marianne also reveals she has found a career where she can operate without the risk of a conflict of interest: doing makeovers.

NEIL'S WHEELS

NEIL YOUNG will never have trouble finding accessories for his Lionel O-gauge freight set again. The toy-train enthusiast (and sometime rock star) is part of a consortium headed by former Paramount chairman Martin S. Davis that just bought the Lionel Trains company. Young, who has two sons with cerebral palsy, has been working with former owner Richard Kughn on developing remote controls that make it easier for handicapped people to use model trains. The new company will continue this work.