Dark Souls developer From Software admitted that their PC port of the notoriously difficult RPG wasn't very good, but that isn't stopping modders from laying on improvements. Now, the PC version has been modded to support 60fps display, a vast improvement over the standard 30fps it was originally stuck at.
A video posted on YouTube includes download links and instructions for the mod. Seems you'll need the to have the original "Durante FSFix" mod from August installed first. The mod was released shortly after Dark Souls: Prepare to Die Edition and removed the game's 1024x720 resolution lock.
Keep in mind that the YouTube video is playing at 30fps, but downloading the .mp4 shows the original 60fps gameplay. Also note that the mod only works in offline mode.