How might I copy on only diffs between two folders into a third?

[Dave_Novak]

Here's the scenario --

* I have Folder A (which contains a copy of my latest source code)
* I have Folder B (which contains a copy of the base version of this same source code)
* Now I wish to create Folder C with just the differences between these two folders. Folder C is to contain only those files that have been updated or added.

Does that make sense? Any suggestions?