Sony expanded Friday on its bid to establish the new PlayStation Portable as a multimedia device by announcing plans to release more movies formatted to play on the handheld game machine.

Sony Pictures Home Entertainment said action films XXX, Hellboy, Resident Evil: Apocalypse, and Once Upon a Time in Mexico will be available for the PSP in mid-April, a few weeks after the device launches in North America. Additional movie releases on the new Universal Media Disc (UMD) optical media format used by the PSP will be made monthly thereafter, according to the announcement.

Sony revealed plans for the PSP last year, positioning it as potential breakthrough machine that would do for digital media what the Walkman did for analog music. Besides the new UMD media format, the device includes built-in wireless networking and 3D graphics capabilities.

While Sony is primarily marketing the device as a game machine, the company has also been gradually emphasizing its capabilities as a music and video device. The company announced last week that the PSP would go on sale in North America on March 24 as part of a package that includes a UMD copy of the hit movie Spider-Man 2.

Sony electronics and entertainment divisions are notorious for not working well together. But Howard Stringer, chief executive of Sony Corporation of America, has vowed to change that with products such as the PSP. "We're working together in real harmony now," he said in a recent interview with CNET News.com. "We understand each other's problems, and we have a better chance of solving some of these issues."