There is a really nice iOS app that has a human vs. human option, BUT it is programmed with the old rules and the app controls how many stones you can drop. You therefore would not be able to replicate games here.
I made a simple tool like this some time ago. It lacks a lot of features (such as undo/redo of moves), but it allows importing from SGF and does scoring. It is not very helpful for analyzing a game that has finished already, but if you have a game in progress where you want to plan ahead, it can help.
