From the FAQ on Disney's park page (link below):
Q. Are there any personal items I should not bring with me into the Theme Parks?
A. Items that you may not bring into the Theme Parks include, but are not limited to:
Items with wheels, such as wagons, skateboards, scooters, inline skates,
shoes with built-in wheels, two-wheeled or three-wheeled conveyances, strollers larger than 36" x 52", suitcases, coolers, or backpacks with or without wheels larger than 24" long x 15" wide x 18" high (coolers required for medication may be stored in a locker or at Guest Relations), and any trailer-like object that is pushed or towed by an
ECV wheelchair or stroller
Alcoholic beverages
Weapons of any kind
Folding chairs
Glass containers (excluding baby food jars and perfume bottles)
Pets (unless they are service animals)
In Disney's Animal Kingdom® Theme Park (for the safety of the wildlife), balloons, straws and drink lids are not permitted.
http://disneyworld.disney.go.com/wdw/common/helpFAQ?id=HelpFAQThemeParkPage#q12
Should be the last question on the page.