Municipal Art Society
MoMA’s before- and after-hours tours
Open House New York
New York Transit Museum
Justin Ferate
Jack Eichenbaum’s Public Walks
Forgotten New York
Joyce Gold
Afoot Walking Tours
Lower East Side Tenement Museum
South Street Seaport Museum
Brooklyn Historical Society
Plymouth Church
Cathedral of St. John the Divine
Tribute Center - WTC perimeter
Urban Oyster
Gotham Sidewalks

Food and drink
Institute of Culinary Education
Nosh Walks
City Food Tours
Chocolate Zoom
Literary pub crawl
Brooklyn Brewery
Slice of Brooklyn Pizza Tour
Scott’s Pizza Tours
Enthusiastic Gourmet
Food on Foot Tours

Music, movies and TV
On Location Tours
NBC Studio Tour
"Wicked" - behind the Emerald Curtain
Hip-Hop Hush Tours
Harlem Hip-Hop Tours
Big Apple Jazz Tours
Harlem Spirituals
Apollo Theater
Carnegie Hall
Met Opera
Lincoln Center
Radio City Music Hall

General/multiple topics
Big Onion Walking Tours
92nd Street Y
NY Like a Native
Gray Line
City Sights NY
NY Party Shuttle Tours
Levys’ Unique NY
Walkin’ NY
A1 NYC Sightseeing
All City NY
Gotham Walking Tours
Uncle Sam's NY
Mike’s NYC Tours
Inside Out Tours

Ghosts of NY
PhotoTrek Tours
Photo Walk-abouts
East Village Walking Tours
Jewish Tours of New York
Hassidic walking tours
NYC Mafia and Jewish Mob walking tours
NYC Mob Tour
Museum of Chinese in America
Audubon Society
"Wildman" Steve Brill
Algonquin Round Table Walking Tours
Mark Twain’s New York
Shop N Strip lingerie tour
Surveillance Camera Outdoor Walking Tours
A Tour Grows in Brooklyn
Yankee Stadium tours
Mets’ Citi Field tours
Madison Square Garden
Bike the Big Apple
Bike and Roll
Manhattan Kayak Company

By boat
Circle Line downtown
Circle Line uptown
New York Water Taxi
NY Waterway
W.O Decker 1930s tugboat and the 1885 schooner Pioneer
Classic Harbor Line
Hidden Harbor Tours
Inactive in 2010: NYC Ducks (previously "Splash Tours")

By helicopter
Liberty Helicopter Tours
Helicopter Flight Services
New York Helicopter Charter
ZIP Helicopters

Scavenger hunt/game tours
Accomplice: New York
Watson Adventures Scavenger Hunts

By cellphone/MP3/download/GPS
Skyscraper Museum
Grand Central Terminal
Greenwich Village Society for Historic Preservation online neighborhood tours
Sex and the City NYC Sites (GPS)
Touchscreen Tour of 5th Avenue (GPS)
City Listen
Walkin' Broadway
Rough Guides
Sound for Sights
CityShow (GPS)

Big Apple Greeter
Bronx Trolley
Central Park Conservancy
Grand Central Terminal
City Hall
Tweed Courthouse
Gracie Mansion
Times Square
Union Square
Lower East Side
NYC Dept. of Parks & Rec
St. Marks Place & 8th Street
National Park Service

SOURCE : NewYorkology