In an official statement, Microsoft said that starting this autumn, the owners of Xbox 360 will have access to exclusive GTA IV episodes.

Microsoft and Rockstar signed the agreement regarding the exclusive content in 2006, but no details are known so far.

“Through Xbox Live, we have a unique opportunity to reach out to our audience in new ways,” said Sam Houser, executive producer and founder of Rockstar Games, back in 2006. “This strategic alliance allows us to craft experiences that fully leverage the on-demand distribution power and sheer size of Xbox Live.”

The launch of GTA IV, which is shaping up to become the biggest event in the entertainment industry, is expected to boost the sales of both gaming platforms, Sony’s PlayStation 3 and Microsoft’s Xbox 360.

It is hard to predict which console will benefit more from the new game, but according to analysts’ predictions, due to the promised exclusive content, Xbox 360 has an edge over PS3. To counter Microsoft’s move, Sony has launched a GTA IV bundle in PAL territories.

For the moment, according to Amazon’s Best Sellers List, the Xbox 360 version of GTA IV is ranked second, behind Wii Fit, while the PS3 version is on the fifth spot.

Last week, Michael Patcher, an analyst with Wedbush Morgan, predicted that the GTA IV release will directly spur sales of 2 million additional PS3s in 2008, versus 1 million Xbox 360s.

Maybe it will be a good idea for Microsoft to reveal more details about the exclusive content it keeps talking about?