LOS ANGELES -- Microsoft ( MSFT) is bringing out the big guns to lure consumers to its Xbox 360 platform.

The catch? Consumers will have to wait until next year.

At a media event here in advance of the E3 video-game conference, the software giant announced that new versions of Grand Theft Auto and Halo -- two of the industry's biggest game franchises -- will be coming to the Xbox 360 in 2007. Grand Theft Auto IV, published by Take-Two Interactive ( TTWO), will hit store shelves in October next year. Microsoft did not give a specific date for Halo 3.

"We couldn't be more excited to have this available on our platform from day one" of its release, said Peter Moore, Microsoft's corporate vice president in charge of its video-game businesses.

The agreement with Take-Two represents something of a coup for Microsoft. For previous iterations of GTA, Sony ( SNE), the industry's biggest player, secured exclusive releases that ensured the games were not available on any other platform until months or years after they were released on Sony's PlayStation game systems.

That's worked out very well for Sony. The latest iteration of the series, Grand Theft Auto: Liberty City Stories has been one of the top-selling titles for Sony's PlayStation Portable game system. Meanwhile, Grand Theft Auto III is considered to have been the key game that drove sales of the PlayStation 2.

Microsoft won't have Grand Theft Auto IV exclusively for Xbox 360; instead, it will get it on the same date that Take-Two will release the game for the PlayStation 3.

But even having it on the same day should blunt some of Sony's advantage. Take-Two, for instance, didn't release Grand Theft Auto: San Andreas for the original Xbox until months after it released a version for Sony's PlayStation 2. By then, Take-Two had already sold millions of copies of the game.

As for Halo 3, the only detail Microsoft released was that it would launch next year. The company also showed some video footage from the game. The original Halo was considered to be one of the only "killer applications" for the first Xbox, helping drive sales of the game machine. Halo 2, released in the fall of 2004, was the top-selling game ever for the original Xbox. Analysts and gamers have been eagerly awaiting news of a sequel.

Microsoft launched the Xbox 360 last fall and has been trying to grab as much market share as possible before Sony and Nintendo launch their rival game machines. However, the company largely missed the holiday shopping season last fall because of supply constraints and had sold little more than three million of the game systems by the end of March.

But Microsoft expects sales and shipments to pick up now that it has a third manufacturing partner for the device. The company expects to reach 5 million shipments by the end of next month and 10 million shipments before Sony releases the PlayStation 3 this November, Moore said.

"Our No. 1 priority was to get consoles to shelves as quickly as we possibly could," Moore said, acknowledging that the company has hit some "potholes" along the way.

Sony plans its own ambitious launch for the PlayStation 3. At a similar press event on Monday, the company announced that it planned to ship 4 million units of the console by the end of this year and a total of 6 million by the end of March next year.

In addition to the blockbuster games, Microsoft is hoping to boost the Xbox 360 by tying it to its Windows platform. The company plans to roll out a service called Live Anywhere that will connect Xbox 360 users with Windows PC and Windows Mobile users. In a surprise appearance at the conference, Chairman Bill Gates laid out Microsoft's vision for the service.

At its most basic level, the service will allow Xbox 360 users to instant message people using the Windows Messenger service on their PCs or cell phones. But the service will also allow users to play games on the Xbox 360 in real time against opponents who may be playing on their cell phones or PCs. And it will allow users to order additional content -- such as weapons or cars -- for their Xbox 360 games using their phones or PCs.

The service will be part of the consumer version of Windows Vista when it ships in January, Gates said. Gates did not say how much the service will cost. Microsoft has two levels of Xbox Live -- a free version that offers basic services and a $70 version that allows users to play multiplayer games.

"We're thinking about this in a holistic way," Gates said of the company's efforts to tie all three platforms together. "Microsoft is probably the only company that will be able to pull this off."

Of course, it remains to be seen how much demand there will be. Less than 10% of original Xbox users signed up for the Xbox Live platform. Microsoft has done much better with the Xbox 360 -- more than half of owners of the new game console are connected to Xbox Live. But the company has not given a breakdown of how many of the Xbox 360 users are actually paying for Xbox Live.

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