The freeSSHd supports Secure FTP and SSH very comfortably.
The name says it all...
freeSSHD is a free implementation of an SSH server. It provides strong encryption and authentication over insecure networks like Internet. Users can open remote console or even access their remote files thanks to buit-in SFTP server.
And the Secure FTP support,
freeFTPd is a FTP/FTPS/SFTP server that enables user to access remote files over TCP/IP network such as Internet. Unlike FTP, FTPS and SFTP protocols provide security and strong encryption of data - great for insecure network.
Both applications can be run on NT based operating system, starting from Windows NT version 4.0. There are no special hardware requirements, any computer that can run WinNT will be sufficient. They use very low amount of resources, but you must keep in mind the memory consumption of applications that your remote users will use and number of users as well.
It works with a very easily managed tasktray icon.