Cyberduck is a open source FTP and SFTP (SSH Secure File Transfer) browser licensed under the GPL with an easy to use interface, integration with external editors and support for many Mac OS X system technologies such as Spotlight, Bonjour, the Keychain and AppleScript.
FileZilla is a fast and reliable FTP client and server with lots of useful features and an intuitive interface.
For more information about this software, see this GROK article: FileZilla: LSU Overview
To download FileZilla, please go to the FileZilla download page.
RBrowser is a full featured free graphic FTP-SFTP client. RBrowser allows the user to manage/browse files on the remote host with an easy-to-use graphic interface. File management includes move, copy, duplicate, compress, delete,set permissions, make links, etc...
For versions compatible with older operating systems, please go to the RBrowser download page.