Remember celebrity magazines? Like Rosie? Like Martha Stewart Living, back before Ms. Stewart's name was shrunk to microtype on her new Everyday Food? So does The Buzz. But all those came from an earlier time. Last week American Express Publishing Corp. announced a new celebrity "publication," courtesy of TV shrink Dr. Phil McGraw, called "The Next Level"-publication because it will be a monthly ad-free newsletter. Newsletter? "We think it's the right format for him," says Mark Stanich, Amex's chief marketing officer. He points out that the luxe-life publisher of Travel & Leisure and Food & Wine also has a substantial newsletter business-but also doesn't dismiss outright the notion the newsletter's a test-run for a magazine. "We are not ruling out anything," he says. One possible reason for caution: Amex's previous attempt at the celeb-branded game, B Smith Style, lasted only a few issues. Meanwhile, notions that the newsletter was originally titled "Up A Notch" before a certain celebrity chef threatened to POW! Dr. Phil into submission, alas, could not be confirmed.