WinSSHD Personal Edition
For Windows users, there are a number of free and inexpensive SSH servers available (sometimes referred to as SSHD--the "D" is for daemon, which is a way of saying "server" in geek-speak). One such program is WinSSHD version 5 from Bitvise, which is available free for personal use.
Run WinSSHD's installer and select the "Personal Edition" for free personal use. If you're using WinSSHD for business, the "Standard Edition" in the same installer is an excellent and inexpensive choice that comes with a 30-day free trial.