Microsoft will extend its Xbox Live online gaming and entertainment network to the Windows platform on 8 May.

The first Xbox Live game to debut on Windows Vista will be Halo 2. Players of the game on both platforms will be able to speak to and send messages to each other. In June Shadowrun will be released, the first game to enable Windows and Xbox Live users to play against one another. A cross-platform version of a third title, UNO, will be available later in 2007.

The online games service, 'Games for Windows – LIVE', will connect gamers worldwide and allow them to communicate with each other. Windows gamers using the Live network will have a single online identity, or gamertag, that works on their PC or Xbox 360. This enables them to see their friends online, send messages and play games with them across both platforms and at no extra cost.

Microsoft corporate vice president Peter Moore said: "The benefits of expanding the Xbox Live to Games for Windows titles is twofold. We're bringing together two communities that share a passion for playing online games, and we’re enhancing the online experience for PC gamers who have long desired seamless game and voice connectivity."

The unified service for Xbox Live and Games for Windows – LIVE will be available in all countries supported by Xbox Live.

Although there's no cost for signing up for a basic Silver membership, premium Gold memberships cost £40 a year. Current Xbox LIVE Gold members will be able to access Games for Windows – LIVE titles at no extra cost.

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