BW Sync

BW Sync is a free Windows graphical interface for rsync.

If you are not familiar with rsync, you are missing out. rsync is a nifty file synchronization program which is usually found on unix-like systems. It can work incrementally, meaning only the differences in files are transferred, so it's a powerful and fast way to copy files between folders, drives, computers, etc. Possible uses include keeping a backup of your documents, mirroring or publishing a website, and many other wonderful things.

Running rsync on Windows is possible thanks to Cygwin, which provides an emulation library for running linux programs. You don't need to install cygwin separately, all the necessary files are included with the BW Sync installation.

In other words, BW Sync itself doesn't do much... the intent is to make rsync easier to use, whether or not you know what a command line is.