The following websites will direct you to external pages. Take your time browsing, there's a wealth of information out there...
Planning Tools
Walt Disney World - The official Website
Tour Guide Mike - automated vacation planner.
Disney Vacation Club
Disney Vacation Club - Members page for the DVC.
DVC by Resale - Resale of DVC points.
The timeshare store - Resale of DVC points.
Specialty Sites
Dead Men Tell No Tales - Dedicated to the Pirates of Caribbean.
Doom Buggies - Dedicated to the Haunted Mansion.
Studios Central - Dedicated to Disney's Hollywood Studios.
Tower of Terror - Dedicated to the Tower of terror.