Activision have formally announced Call of Duty 4: Modern Combat, alongside the good news that it will be out on PC in addition to Xbox 360 and PlayStation 3:

"Call of Duty 4: Modern Warfare is the most intense, visceral title we've ever created," says Jason West, co-studio head and project lead, Infinity Ward. "The single player campaign is a well-paced, non-stop action experience. As the story unfolds, the player is introduced to new gameplay at every turn - one moment you are fast-roping from your Blackhawk helicopter after storming into the war zone with an armada of choppers, the next you are a sniper, under concealment, in a Ghillie suit miles behind enemy lines, the next you are engaging hostiles from an AC-130 gunship thousands of feet above the battlefield - get ready for the fight of a lifetime."

Check out the high def teaser trailer if you missed it.

Can I just say how wet I am for this. (On PC of course, consoles suck.)

yeah i've got half a bar in anticipation

It sounds interesting, but theres a lot of other games far ahead of it on my "must play" list.