SSH is a secure way to connect to another computer system. This protocol supports a telnet alternative (usually called SSH itself), a secure file copy program (SCP) and a secure FTP program (SFTP). The SSH protocol also lets you establish secure connections with other programs or protocols through the use of port forwarding. This means that mail protocols, vnc, and other programs can be used with encryption between two machines.
From the OpenSSH Project History Page:
OpenSSH is a derivative of the original free ssh 1.2.12 release from Tatu Ylönen. This version was the last one which was free enough for reuse by our project. Parts of OpenSSH still bear Tatu's license which was contained in that release. This version, and earlier ones, used mathematical functions from the libgmp library. That library was also included with these early ssh versions. The libgmp library is made available under the (LGPL) Lesser GNU Public Licence, although versions of that era were under the regular (GPL) GNU Public Licence.
The OpenSSH for Windows package is a repackaging of the OpenSSH port to the Cygwin environment. While not a native Windows port, this goal of this distribution has been to run the OpenSSH client and server programs with as little of the Cygwin environment as possible. This helps Windows administrators who might be unfamiliar with the Unix environment and helps users with access to the Windows command line interface. As with the OpenSSH and Cygwin packages, this software is also being distributed free to any user who is looking for a more secure way to remotely administer their Windows machines.
Microsoft has a lot of Windows configurations (Counting releases since Windows NT 4.0, there are over 10!). I really cannot test all configurations possible on all of these releases. Following is a list of the conifgurations I have tested my OpenSSH for Windows with. All tests were conducted with default NTFS permissions. Users who change their default security configurations will have to sort out things if the package does not work.
OpenSSH for Windows Install Details / Updated: 13 June 2003