These days, preschoolers need electronic organizers to manage their busy schedules.

Even parents lucky enough to get their children into the highly coveted slots at top-tier city preschools are seeking out extracurricular enrichment for the youngsters. It’s gone beyond traditional arts-and-crafts classes and sing-along sessions. Today, tots can learn such essentials as “baby sign language,” Italian meal preparation, or chemistry basics.

In addition to preschool, which starts next week for most youngsters, many parents feel that giving their children an edge means enrolling them in a bevy of before- and after-school classes.

“We’re seeing parents who want to fill up every waking moment,” the founder of miniMasters, a children’s activity center in TriBeCa that opened in April, Marie-France Greer, said. “I think it’s a New York thing. Parents are trying to expose their kids to as much as possible, and you almost feel left out if you don’t.”

In addition to its American Sign Language classes, miniMasters offers Suzuki-method violin, piano, and guitar lessons for children 3 and older; and courses in French, Spanish, and Mandarin to its members.

A group of 28 children who attend the pre-K program at Riverdale’s Horace Mann School supplement their thrice-weekly classes with a customized program at Kidville, an activity Center on East 84th Street. Together with their pre-school peers, the children partake in arts, cooking, music, and exercise classes at the center.

Kidville boasts more than 5,000 members between its Upper East Side and Upper West Side locations, which opened in January 2005 and May 2006, respectively.

Classes at the centers can fill up months in advance. Online registration for Fall 2007/Winter 2008 Kidville University, a twice or thrice weekly educational arts, music, and exercise program for 2- and 3-year-olds, opened yesterday at 6 a.m. — and at 6:02 a.m., the first application arrived, a cofounder, Rammy Harwood, said.

That program serves a total of 300 youngsters at the two locations, and there are about 50 names on the waiting list, according to Mr. Harwood.

“I try to find the right balance of school, plus whatever fits into their schedule,” a Kidville member with four young children, Jennifer Rosenblum, said. “I try to expose them to as many things as possible, which can mean two or three things a season.”

Ms. Rosenblum has enrolled her children in a variety of Kidville courses, including “Silver Spoons & Plastic Plates” on international cuisine, “Hip-Hop Dance Party” on rhythmic expression, and the musical performance seminar, “Little Maestros.” Her preschool-age children attend Park East preschool.

Those classes cost about $700 each, so Ms. Rosenblum counts on spending $1,500 to $2,000 a child each semester. Kidville school-year semesters run 17 weeks.

Factor in that those prices are in addition to preschool tuition, which can cost nearly $30,000 annually at some prestigious city private schools.

“Parents have decided that preschool is not enough,” the founder of Manhattan Private School Advisors, Amanda Uhry, said. “But no 2-year-old needs to know about the cuisine of Mexico,” she said. “No 3-year-old needs to know how to make sushi. Who are they going to make it for — their babysitter?”

And contrary to the idées fixes of many city parents, all these activities don’t necessarily help get them into top private schools. In some cases, overscheduling can be counterproductive, Ms. Uhry said.

“It can be dangerous because you end up with a very stressed preschooler,” Ms. Uhry said. “How is a child going to do well on the ERB” — the private school entry exam — “if they’re thinking,‘If I don’t do well in soccer, or if I don’t do well in art class, mommy will be upset.”

A mother of a 2-year-old, Tracy Geller Doyle, said she struggled with her decision to enroll her son in two classes — a music class at Hands On, and an exercise program at Kids in Sports, both on the Upper East Side. “I didn’t want to overwhelm him,” Ms. Geller, who is 40 and lives on the Upper East Side, said. “I didn’t want to be one of those parents who overbooks her children. Maybe after the first half of the year, I’ll feel differently, but for now, I’m happy with my decision.”

So, too, is Kathleen Reyes-Levine, a Battery Park City resident. Ms. Levine, 35, said her 3-year-old daughter and 15-month-old son enjoy the the arts and dance classes they take at miniMasters. “Preschool is never going to be enough,” she said. “Kids have so much energy and they’re so curious. I don’t want to hold them back just because some people think that kids are overscheduled. I don’t want to limit their potential.”