automate secure download

I would like an efficient, free system to deliver files from my system to remote systems (not administered by me). I need a solution that is secure (HIPAA-compliant) and dead simple for the end user. The end users are EXTREMELY resistant to change or any effort to learn.
All systems are Windows XP or higher. I would like to create a script that would create a secure connection (ssh, vpn, etc.), pass ntfs credentials specific to each end user, check a folder specific to each end user for new files, download any new files and disconnect. I'd schedule this script to run every few hours.
I have explored the built-in FTP command in windows, but cannot find a way to secure the connection within that command set.

Any ideas?