LOS ANGELES – Warner Bros. is buying the Flixster movie-discovery service to help people flip through the movies they’ve bought and access them on the go.

Flixster is already installed on 35 million iPhones, BlackBerrys and other mobile devices. It offers an array of listings, photos, trailers and reviews from its subsidiary, Rotten Tomatoes.

With the deal announced Wednesday, Warner Bros. hopes to latch onto Flixster’s popularity to help it launch a system for storing movie purchases on distant servers known as “the cloud.” Such a system will let people watch movies they’ve bought on any device, regardless of the format.

The system, called UltraViolet, is set to launch in the U.S. this year as studios try to boost sales of digital movies to offset falling revenue from physical discs.

Thomas Gewecke, president of Warner Bros. Digital Distribution, said it will be important to give the digital movie plan a head start by having it promoted on a popular movie-search service — the San Francisco-based Flixster.