The Nickelodeon Suites Resort has what looks to be a fairly nice waterpark. I've never been (and you may not want to surround yourself with Nick 24/7), but I came across it in my search for hotels near Disney.

book a marriott vacation club as a hotel for a week. they are suites with kitchens, patios, and it's like a mini-resort. Marriott has 5 mvci's in orlando. We stayed at Cypress Harbor last year with a 5 and a 3 year old and loved it. tons of pools, across from sea world, 10 min. to disney.

Hyatt orlando. nice pool but not much fun if it is cold. Disney has a waterpark

Reunion Resort in Orlando has an onsite waterpark

Spring break trip to exotic locale cancelled!! I need to find a replacement trip -- and a hotel with a lazy river/waterslides would be perfect. Kids are 7 and 4. Thanks!