In an effort to place itself at the forefront of the mobile-games movement, Yahoo announced today that it has launched its own game development studio; acquired Stadeon Inc., another development studio; and named Stadeon CEO John Cahill the head of the Yahoo Games Studio.

Yahoo already provides its users with free multiplayer versions of card and board games; now it plans to take games like hearts, backgammon, and dominoes to mobile phones.

"Casual games...are extremely popular in the emerging mobile-entertainment market. They are just the right format for today's mobile devices and the broad range of users who like to play them," said Geoff Graber, general manager of Yahoo Games, in a statement.

Stadeon's first game, Carousel, can already be played by multiple gamers using their mobile phones. Yahoo hopes to capitalize on the company's development of those multiplayer and multiplatform tools.

Before coming to Stadeon, Cahill worked with Shockwave.com, SegaSoft Networks, and Trintech Group. He will direct game-based operations at Yahoo and look for ways to expand the company's cross-platform games strategy.