FTP Synchronizer - Secure and high performance FTP File Sync product
FTPbox - FTPbox is an open-source application that allows you to synchronize your files to your own host...
GNOME Commander - GNOME Commander is a "two-pane" graphical file manager for the GNOME desktop environment.
Dropbox - Online Sync and File Sharing
Polo File Manager - Software for Linux
Syncany - Syncany is an open-source cloud storage and filesharing application.