Disney has two options - one professional and one, well, unprofessional.
A professional Honeymoon Portrait Session from Disney Event Group Photography will run you $310 and can take place at any Walt Disney World resort or theme park (except the Magic Kingdom), although admission to the parks is not included in the price. You will receive a 4x6-inch print of every image and a 4x6-inch white, Disney-themed album containing 20 prints chosen by the photographer. Casual attire is required, and comfortable walking shoes are recommended. To schedule a Honeymoon Portrait Session, call 407-827-5099.
You can call the same number to schedule a professional Theme Park Bridal Portrait Session in wedding attire at Epcot, Disneys Hollywood Studios, or Disneys Animal Kingdom before the park opens. The cost is $650 for 12 4x6-inch prints in a folio and a 4x6-inch print of every image. The price for 12 8x10-inch prints in a folio is $900.
A non-professional, 30-minute private resort photography session with Disney's PhotoPass will run you $49.95, and you can choose one of three combinations of prints: two 8x10s and three 5x7s; two 5x7s and four sets of two 4x6s; or seven 5x7s. The $99.95 package gives you your choice of print package plus all images on a PhotoPass CD (anywhere from 40-70 images, depending on the pacing of the session). The locations available are the Beach Club, Grand Floridian, Polynesian, Animal Kingdom Lodge, or Wilderness Lodge. You can book a private session up to 30 days before you arrive by calling 407-934-4004.
As a previous poster said, if you want professional photos and don't need them taken inside the park, you'll get a lot more bang for your buck by going with a local wedding photographer - most of them offer inexpensive engagement portrait sessions, and you can get plenty of recommendations on this board.