Although this book is from 2001, it will still be useful for NYC visitors w kids ages 2-14. The chapters are well-organized and include subjects such as Planning your Trip, What Kids Like to See and Do, Neighborhood Strolls, For the Active Family, Shopping, Entertainment, Restaurants (by cuisine, price, neighborhood) Accommodations, Side Trips and more. It's small enough to carry while you're in town so you can always have it handy.
This is the 7th Edition of the book. (2001 copyright) - there are some great ideas for what to do in NYC with kids.