SyncToy

Microsoft SyncToy is a free PowerToy for Microsoft Windows XP that provides an easy to use, highly customizable program that helps with the copying, moving, and synchronization of different directories. SyncToy can manage multiple sets of directories at the same time; it can combine files from two folders in one case, and mimic renames and deletes in another. Unlike other applications, SyncToy keeps track of renames to files and will make sure those changes get carried over to the synchronized folder.