Hi there Yvonne,
Celebrating a birthday at The Happiest Place on Earth is THE best! Our family has enjoyed many magical birthday memories while at the parks.
There is no where to sign up your child, an easy way to let Cast Members know your son is celebrating his special day is to get a birthday button for him to wear. Be sure to stop by City Hall on Main Street, U.S.A. in Disneyland Park or at Guest Services in Disney California Adventure Park to get your son his free ‘It’s my Birthday’ button to wear during your vacation; Cast Members that see him in the parks will be sure to send birthday wishes all day.
You could make reservations at one of the restaurants that offer
Character Dining Experiences for your son’s birthday. Disney Characters stop by your table for autographs and pictures. Be sure to tell your Server that you are celebrating a birthday too, you never know what magic may come your way.
You can sprinkle some pixie dust on the big day by ordering a personalized birthday cake if you're dining at select table service restaurants. Call the Disney cake number at (714) 781-3463 to order one, they will need at least 72 hours notice prior to your magical date needed.
I hope this helps you. Please feel free to visit us again with any other questions you may have. Wishing your prince a very merry birthday and that you have a Zip-A-Dee-Doo-Dah time!
chEARs!
~ Lynette