Fans of Dark Souls may have worried when the PC version, Prepare to Die Edition, was announced to have new bosses and areas that weren't available elsewhere, but their worries were put to rest today as Namco Bandai announced that the new content will also be available for existing owners of the Xbox 360 and Playstation 3 versions. The new additions will come in form of downloadable content under the name 'Artorias of the Abyss' and will take you to unfamiliar lands. Not much else is known, and maybe it's for the best as the world of Dark Souls is all about finding things out on your own.
On a related note, the PC version has also been confirmed to be sold on Steam when released, which I would think would be an obvious choice, but will also be offered through Microsoft's Games for Windows service. Sorry petitioners; it looks like Games for Windows Live will definitely happen. Let's just hope the Steam version is similar to Batman: Arkham City in that it includes both Steamworks and Games for Windows Live capabilities.
The piece of DLC will be released this Winter and will cost a measly $15, or 1200 Microsoft Points. The PC version will be released August 24th with an unannounced price point.
http://youtu.be/M3KOjeWd4ZY