Microsoft Chairman Bill Gates called the early success of its Xbox 360 game console a role-reversing change of fortune for the software giant looking to overtake market leader Sony. Gates also announced Microsoft would offer an Xbox 360 that doubles as a set-top box for its fledgling Internet television (IPTV) service, or a “living room device that does it all.” The Xbox 360, Sony’s PlayStation 3 console and Nintendo’s Wii game machine are locked in a battle for leadership in the $30 billion global video game market. Sony and Nintendo came out with their offerings in November, a year after Microsoft introduced the successor to the first Xbox.