I have been using a free FTP program called WinSCP for a while now. I used to use WS_FTP by IPSWITCH, but I found WinSCP and it works fine. WinSCP allow me to SFTP my files up and down from my server as well as download backups of my websites using SCP. Explanations of the protocols are below. One of my favorite features in WinSCP is that you can throttle the bandwidth on transfers. I don't want to overload my server by downloading at the full speed of my cable connection.
SFTP (SSH File Transfer Protocol)
Despite SSH in its name, it is designed to work over any reliable data stream, but WinSCP supports only operation over SSH, which is also by far its most common usage.
SFTP is operated over SSH, it is a secure protocol. In its basic functionally it is similar to old FTP, while having better designed sophisticated functionality.
SFTP is more platform independent, compared to both FTP and SCP.
SCP (Secure Copy Protocol)
SCP (Secure Copy Protocol) is mostly used with SSH-1. SCP is an older protocol but almost universally supported on Unix-like platforms as part of an SSH protocol suite. It is rarely supported on other platforms. SCP is a descendant of “rcp.”
The SCP protocol allows only file transfers in both directions. WinSCP offers other features, implemented using common shell commands including cd, ls, pwd, rm, ln, etc. WinSCP is unlike command line SCP clients (which allow only file transfers). Other SCP clients require full shell access and permission to execute other commands in addition to SCP. For access to non-UNIX servers it is necessary that the server have at least a UNIX-like shell.
FTP (File Transfer Protocol)
FTP is the oldest protocol of the three. FTP is the most widespread transfer protocol of today. FTP is insecure, sending all data (including passwords) unencrypted. Although there exists secure variants (FTP over SSL), they are not supported by WinSCP. Functionally it is inferior and not as secure as SFTP. FTP is less platform independent than later versions of SFTP, mainly in respect to directory listing.
WinSCP should run on any system running Windows 95 or later. WinSCP requires at most 10 megabyte of free disk space. There is a portable version that runs on a U3 Thumbdrive. You can store all of your website settings in an INI file and move it to a different computer.
WinSCP also runs on Linux platforms with Crossover 4.x or later is running. Crossover allows for a Windows program to run in a Linux platform.