Happy 4th birthday to your little Princess! This is going to be a very memorable birthday for her! I'm sorry to tell you that the free birthday ticket offer is no longer offered at Walt Disney World.
There are two Princess character dining experiences that I can recommend to you. The first one is breakfast or lunch at Cinderella's Royal Table in Magic Kingdom. Most of the time Cinderella will be found on the main floor greeting her guests. During the meal she and the other Princesses will mingle through the dining room, sign autographs and pose for pictures with the guests. The other character dining experience is Akershus Royal Banquet Hall in Epcot. It's the same concept. Lots of beautiful Princesses, adoring little girls and great food. You can call (407)WDW-DINE to make your reservations, which they will accept up to 180 days prior to your visit.
For special custom cakes you can call the Disney cake line at 407-827-2253. They will guide you through choices, give you ideas and, of course, answer your pricing questions. You can visit
www.disneyworld.disney.go.com/celebrations to look at one of the Princess cakes that they offer. They will need to order a few days in advance.
I wish your little girl a wonderful and magical birthday!