From their website:
Simply play Toontown daily between now and July 31, 2009 11:59 PDT and each day you log in and play, you will automatically be entered for a chance to win (must be 13 years old or above).
One grand prize winner and three guests will enjoy:
* Round-trip airfare
* Disney Resort hotel accommodations
* Disney Theme Park tickets with Park Hopper® option
* And MUCH more!
Enter here to win your own celebration at Disney World!