Now new game software is promising to allow them to play those same complex games against friends using other devices, such as PCs or phones running Google's Android operating system.

The development is an important one for the video game industry and for the smart-phone platforms, said Ben Bajarin, a consumer technology analyst at Creative Strategies, an industry analysis and consulting firm.

"It makes games more valuable when they can (be played) cross-platform," that is, on a variety of devices, Bajarin said.

On Thursday, game maker Namco Networks plans to begin selling a new version of its pool game, "Pool Pro Online 3," in the iPhone app store. The game features new technology developed by Namco called UniteSDK. Later this year, Namco, best known for making "Pac-Man," will release the game for other devices, including Mac and Windows-based PCs, Android and Windows Mobile smart phones and so-called features phones, which don't have a full operating system.

Once those versions are released, iPhone users will be able to shoot pool against players on those platforms. Namco also plans to incorporate the technology into some of its other games and to license it to developers.

Namco's announcement follows a related one by online gaming company Bigpoint and game development company Unity Technologies. On Monday, Bigpoint said it has created a racing game using Unity's software that will allow iPhone users to compete in real-time against friends who are playing on PCs.

Although the game is only a test version, company officials said Bigpoint plans to release the game at the E3 trade show in June and that it will eventually be playable on a range of devices, including other smart phones.

The idea...