THERE are about 25 online reservation sites on the Web, with varying degrees of usefulness.Some provide instant results, while other sites take hours to confirm reservations through e-mail correspondence.

Here are three sites New York diners can use:

OpenTable.com Offers reservations at New York restaurants including Alaia, Domenico, Oyster Bar at Grand Central Terminal. System used: Instant reservation with credit card.

Foodline.com New York eateries include Babbo, The Globe, ’21’ Club. System used: Instant reservation with a credit card.

RestaurantRow.com Local eateries include Four Seasons, Balthazar, La Cote Basque. System used: Instant reservation with credit card and table assignment via e-mail.–