Who was that little girl covering her ears and frowning while the newlyweds will & kate kissed on the balcony?

That's Prince William's goddaughter, 3-year-old Grace van Cutsem, who was one of the official bridesmaids (there are no "flower girl" roles in traditional British weddings, so children are often included as bridesmaids or pages). She is the daughter of Lady Rose Astor and Hugh van Cutsem, and great-great-great-granddaughter of William Waldorf Astor, a New York-born lawyer and politician who later became a member of the British Aristocracy. (The Waldorf Hotel was one of his pet projects.) Little Grace was also pouting for part of the carriage ride; apparently, the crowd of adoring fans got a little too noisy.