SyncToy

SyncToy, one of Microsoft's PowerToys for XP, is a very useful tool for backing up and synchronizing data between multiple storage devices. It is easy to set up and use. I mostly use SyncToy to back up my data to my external hard drive with just a few clicks of the mouse. This is much easier and faster than my old method, backing up manually by dragging folders and files one by one — often forgetting which folders are new or backed up already. Sometimes I just get lazy and go without backing up my data for months because the process was not too much fun. Now, I back up my data every other weekend with SyncToy. The small application can also be used to synchronize the creation, deletion, and modification of data on multiple computers such as between a laptop and a desktop.

Download SyncToy here. It is free. It is a great utility for the PC. You may also check out SynToy's WhitePaper here.