Microsoft has announced that its worldwide sales of the new video game, “Halo 3,” reached $300 million for the first week that the game has been available. 

The company also indicated that subscriptions for its Xbox Live online service have caused a “record” number of players to sign up.  Xbox Live allows multiple gamers to play the game at a time and also provides gaming with other players over the Internet through its servers.

Microsoft indicated that so far all three versions of "Halo" games have sold more than 20 million copies. Based on the fact that “Halo 1” and “Halo 2” together sold about 14.8 million copies that means that “Halo 3” has already sold about 5.2 million copies.