The Pradas and Armanis will most likely appear soon enough, but it’s comforting to discover that when celebrity types shop for the bulk of their kids’ clothing, they go to The Gap like everyone else. The pricier boutiques are reserved for specialty stuff, or party dressing. Actress Phoebe Cates (a.k.a. Mrs. Kevin Kline) favors Oilily (870 Madison Avenue, near 70th Street; 628-0100) for pants and dresses in eye-popping prints for just-turned-5 Greta. Seven-year-old Owen wears his sweats big and baggy, so Cates heads to Morris Bros. (2322 Broadway, at 84th Street; 724-9000) for the baggiest around, but she’ll pop into BéBé Thompson (1216 Lexington Avenue, near 82nd Street; 249-4740) for Chevignon sweats (“They wear so well”) and for suits (“I buy him a Paul Smith each year”). Bébé Thompson is also high on actress Tracy Pollan’s (a.k.a. Mrs. Michael J. Fox) list for Petit Bateau T-shirts, bathing suits, and twirly dresses for the twins, 4-year-olds Aquinnah and Schuyler. Another Pollan favorite is Catimini (1284 Madison Avenue, near 91st Street; 987-0688) – she likes the French-cut pants and outerwear for Sam, who’s almost 10, leggings and stretch pants for the twins. It’s Polo/Ralph Lauren (867 Madison Avenue, at 72nd Street; 606-2100) for Sam’s sport jackets, Coco & Z (222 Columbus Avenue, near 70th Street; 721-0415) for stretchy velour dresses for the girls, and Magic Windows (1186 Madison Avenue, near 87th Street; 289-0028) for splurges. Cari Modine (a.k.a. Mrs. Matthew Modine) is Matthew’s manager, and mom to Ruby, 9, and Bowman, 13. For parties and such, Ruby has a surprising soft spot for lacy girly dresses and skirts, and she especially likes the ones in The Wooden Soldier catalogue (800-375-6002). Bowman is so tall that Modine turns to Brooks Brothers men’s department for sport jackets but Pacific Sunwear (364 Sixth Avenue; 228-2316) for what she calls his “California happy clothes.”