From Michael Wolf at Gamerscoreblog:
Let's put the rumors to rest, please.
Many folks out there on the Internet may have seen this story. Or this one. Or even this one.
Here's the truth:
Yes, Microsoft provided the image that is published in the Games for Windows cover story in the Holiday issue of PC Gamer magazine.
Yes, this image contains what looks to be box shots of Gears of War with the Games for Windows branding bar on the box art.
NO, this is not a confirmation, leak, tease, or sly viral attempt to announce, confirm, or admit that Gears of War will be published for Windows.
Here's what happened: These images were created using draft templates for the Games for Windows box art and a variety of Microsoft Game Studios cover images. Gears of War was accidentally included by the artist as one of the MGS titles used as examples to show what our retail setup would look like. This DOES NOT indicate a confirmation that Gears of Wars will be a Games for Windows title -- it was a concept image created by a concept artist, nothing more. In fact, if you look closely you’ll also see that Age of Empires III and Rise of Legends are also branded Games for Windows, and this is not actually the case (Age of Empires III: The Warchiefs is a Games for Windows branded game, but not the original Age III).
We created this image around the E3 timeframe when we were first preparing to announce and show our Games for Windows retail efforts. Shortly after the insanity that is E3, we noticed the box art, and the image was supposed to be removed from circulation. When we provided the package of art assets to PC Gamer for their cover story, we zipped up a directory of our already-public E3 assets as well as more current images (many of which PC Gamer did not use). Unfortunately, we didn't realize that this image was in that directory, and it just happens to be the one that PC Gamer figured prominently in their story. Our bad.
We're incredibly excited about the success of Gears of War on Xbox 360, but we have nothing further to announce about Gears of War, or any other platforms it might come to, at this time.
Now stop rumor-mongering and get out there and start fragging some Locust!