Goodsync

From Siber Systems:

GoodSync is an easy, secure, and reliable way to automatically synchronize and back up your photos, MP3s, and important files. Backing-up and/or synchronizing your critical documents is as easy as one click, and can also be scheduled using a variety of automatic options. True bi-directional file synchronization prevents any data loss. GoodSync can be used to automatically synchronize data between your desktop PC and laptop, home and office computers, computer and removable devices (USB Key, Flash Drive, CDRW disc), over a local network or the Internet using FTP, SFTP, and WebDAV.