Fantasia doesn't have any one big presence in Disney's parks and resorts - there's no Fantasia: The Ride, but there are several smaller appearances and references to Disney's third animated feature if you look closely enough. Here are a few:
WALT DISNEY WORLD
Probably the closest thing to a Fantasia attraction are the Fantasia Gardens and Fantasia Fairways miniature golf courses, located behind the Dolphin resort near Epcot.
A quick tribute to Fantasia appears in Disney's Hollywood Studeio's The Great Movie Ride(TRIVIA: This scene, featuring Sorcerer Mickey direcing a whirlwind of water was originally planned to be the tornado that transports you to the next scene, The Wizard od Oz).
One section of the All Star Movies Resort is themed to Fantasia, as is that resort's pool.
Disney World's usual night time parade (on hiatus as of this writing), Spectromagic, features several illuminated Fantasia floats.
Yen Sid's magic hat, apparenly now passed on to his apprentice, shows up to cause lots of trouble for Donald Duck in Mickey's Philharmagic.
Disneyland Paris' version of the Storybook Land Canal Boats, Le Pays des Contes de Fées, features Fantasia's Chernobog cowering from the sun above the little village.