Rapture of cookedgamers posted in the HBO forum that Gearbox Software, the company that ported Halo from the Xbox to Windows, has announced a new project, apparently called WarStory. He's linked to a single page at http://www.warstorygame.com which appears to be registered to Gearbox.

Randy "DuvalMagic" Pitchford has posted in the Gearbox forum, linking to that site, and saying an official announcement is due "very soon".

There's no information on the new site itself save for a single quote:

"The problem with these games is that they promise to let us live the life of a soldier in combat, but they're not really putting us there. Real soldiers know that in combat, you live and fight as a team. Leadership counts. Good tactics win. Poor leadership and bad tactics get you slaughtered."

The quote is attributed to US Army Airborne Ranger Colonel John Antal. Sounds like they're going for realism in this one.