Check the red tutu at the door: Creative Movement At The Joffrey Ballet School (434 Sixth Avenue, at Tenth Street; 254-8520) is a strictly pink affair. The hour-long class gives 3- to 4-year-olds a systematic introduction to the motor skills and discipline at the heart of classical dance. "Making a cookie" will soon become first position and "making a rainbow" second, but until then, creative movement is a combination of tummy power, jack-in-the-boxes, and colored ponies. "At 3 years old, it's introducing them to their bodies and how their bodies are going to change," explains instructor Elizabeth D'Anna. Dance class, she says, teaches kids about "stretching their legs, pointing their feet, holding their backs, putting two movements together for coordination, understanding the rules of the classroom, discipline, and getting along with other children." Truly emerging choreographers can also stoke their creative fires at Dance Theater Workshop (219 West 19th Street; 691-6500) with Ellen Robbins, who has been teaching a mix of technique, improvisation, and composition for over 30 years and whose alums include Claire Danes and Julia Stiles. "I pride myself on the fact that they look like who they are when they're dancing," Robbins says. Her 5-year-olds use one of Mozart's thirteen variations on "Twinkle, Twinkle, Little Star" to choreograph a 30-second lullaby; older kids might grapple with Vermeer, Tagore, or Bach for choreographic inspiration. "She was, without exaggeration at all, the best dance teacher I've ever had," says Stiles. "She makes you really open and uninhibited and taught me to express certain emotions physically. I owe a lot of my acting ability to her."