TIW is $75 for AP holders. It entitles you to a 20% discount off food and beverages, alcohol included, at participating locations. You can use the TIW discount for up to 10 people, but they all have to be at the same table and on the same check.
Also, resort valet services are complimentary to members, but only 1 vehicle per card. Just present a dining receipt at the valet stand upon retrieving your vehicle.
You can get reimbursement for parking at all theme parks by showing your membership card at Guest Relations. If you enter the park after 5:00, you can just show your membership card at the toll plaza to enter the parking lot for free.
There are some black-out dates for TIW:
Mothers Day, Easter Sunday, Independence Day, Thanksgiving Day, Christmas Eve, Christmas Day, New Year's Eve and New Year's Day.
When you use TIW, they automatically add an 18% gratuity. And it's 20% at Victoria and Albert's.
Most TS locations participate, and a handful of CS locations.
Here's the list:
Disney's All-Star Movies Resort – World Premiere Food Court
Disney's All-Star Music Resort – Intermission Food Court
Disney's All-Star Sports Resort – End Zone Food Court
Disney's Animal Kingdom Lodge – Boma - The Flavors of Africa, Jiko - The Cooking Place, Victoria Falls, Sanaa
Disney's Beach Club Resort – Beaches & Cream Soda Shop (excludes take-out shop), Cape May Cafe, Martha's Vineyard Lounge
Disney's BoardWalk – ESPN Club, Flying Fish Cafe, Kouzzina, Bellevue Lounge
Disney's Eagle Pines and Osprey Ridge Golf Club – Sand Trap Bar & Grill
Disney's Caribbean Beach Resort – Shutters at Old Port Royale
Disney's Contemporary Resort – California Grill, Chef Mickey's, The Wave, Outer Rim Lounge
Disney's Coronado Springs Resort – Maya Grill
Disney's Fort Wilderness Resort & Campground – Crockett's Tavern, Hoop-Dee-Doo Musical Revue (9:30 p.m. show only), Trail's End Restaurant
Disney's Grand Floridian Resort & Spa – 1900 Park Fare, Citricos, Garden View Lounge, Grand Floridian Cafe, Mizner's Lounge, Narcoossee's, Victoria & Albert's (excludes Chef's Table)
Disney's Old Key West Resort – Olivia's Cafe
Disney's Polynesian Resort – Kona Cafe, 'Ohana, Tambu Lounge, Disney's Spirit of Aloha Dinner Show (Late show only)
Disney's Pop Century Resort – Classic Concoctions, Everything Pop Shopping and Dining
Disney's Port Orleans Resort – French Quarter - Sassagoula Floatworks & Food Factory, Scat Cat's Club
Disney's Port Orleans Resort – Riverside - Boatwright's Dining Hall, River Roost
Disney's Saratoga Springs Resort – The Artist Palette; The Turf Club Bar & Grill
Disney's Vero Beach Resort – The Green Cabin Room, Shutter's and Sonya's (except Sunday Brunch)
Disney's Wilderness Lodge – Artist Point, Territory Lounge, Whispering Canyon Cafe
Disney's Yacht Club Resort – Captain's Grille, Ale and Compass Lounge, Yachtsman Steakhouse, Crews Cup Lounge
DOWNTOWN DISNEY – Marketplace - Cap'n Jack's Restaurant, Raglan Road Irish Pub and Restaurant, Planet Hollywood
Epcot – Tutto Italia Ristorante, Chefs de France, Nine Dragons Restaurant, San Angel Inn Restaurante, Bistro de Paris Restaurant, Le Cellier Steakhouse, Biergarten Restaurant, Restaurant Marrakesh, Restaurant Akershus, Rose & Crown Pub & Dining Room, The Garden Grill, Coral Reef Restaurant
Disney's Hollywood Studios – Hollywood & Vine, 50's Prime Time Cafe, Tune-In Lounge, Mama Melrose's Ristorante Italiano, Sci-Fi Dine-In Theater Restaurant, The Hollywood Brown Derby
Magic Kingdom Park – The Crystal Palace, Cinderella's Royal Table, Liberty Tree Tavern, The Plaza Restaurant, Tony's Town Square Restaurant
Disney's Animal Kingdom Theme Park – Tusker House Restaurant, Pizzafari, Flame Tree Barbeque, Restaurantosaurus