It’s a good day for PC Dark Souls players. A day after GFWL was definitively excised from the game, framerate unlock has been brought back.
To be clear, From Software never added this feature, leaving it to a fan to enable it via a mod called DSFix. Now, another fan has adapted that mod for use on Steamworks.
The modified, er, mod, is called DSfix 2.3. You can learn more about it and get it here.