WinSCP – Open Source FTP Client for Windows
For Windows only: Other than using Filezilla or FireFTP FTP clients, another free and open source alternative is WinSCP – the open source SFTP and FTP client for Windows. It excels in file transfer and employs the Secure Shell (SSH) for secure file transfer and supports both the SCP and SFTP protocols.
It’s major limit is that unlike Filezilla it is not a cross-platform FTP client and does not support FTPS (FTP over SSL)
You could also fetch the portable version of WinSCP for your thumb drive at Portable APPS.
The WinSCP project took off in 2000 and is released under the GNU GPL License