This is from Kid's Night Out's website; I have seen lots of positive reviews on using them to babysit at the resort:
Additional Information
Water activities are not permitted. (bathing, boating, swimming)
When traveling to a theme park with a caregiver, transportation cannot be by private vehicle. Shuttle, chartered transportation, taxi, or Walt Disney World transportation service is acceptable.
Please be aware that theme parks do not allow our caregivers admittance for free. A mothers or fathers helper will need a theme park ticket purchased for their admittance.
Our caregivers are available 24 hours a day, 7 days a week. Reservations may begin as early as 6:30am and/or may begin as late as 11:00pm. There is no limit to the number of hours that you may utilize the services of a caregiver. (During the Walt Disney World Marathon in January, reservations may be booked as early as 3:00am.)
If a caregiver is needed for an eight (8) hour shift or more, we request that a meal be provided for the caregiver.
We accept credit card as the only form of payment. Visa, MasterCard, American Express and Discover are accepted for your convenience.
Our caregivers are able to accept a gratuity in cash if you feel that you were extended exemplary service.