Related to the story above, an update to the thread about Dark Souls Prepare to Die Edition Steam migration has word that plans to migrate the action/RPG sequel from Games for Windows LIVE to Steamworks are being delayed for further testing (thanks GameSpot):

We are working hard to finalize the process to move your Dark Souls: Prepare to Die saves and achievements to Steam. We need to conduct additional testing and we are now targeting December to begin this process. We'll have more information in the coming weeks. Thank you very much for your patience!