Windows/Mac/Linux: Inspired by our post on Linux backup utility Back in Time, but finding it lacking encryption and network powers, Rob Oakes wrote his own Python-based utility to back up Windows, Mac or Linux machines across local machines or networks.
Rob's app is styled a lot like Back in Time and other backup utilities, with simple folder adding and backup buttons to get the job done, and it offers scheduling for automated, incremental backups. The key features, though, are its support for backing up over secure SSH/SCP connections, WebDAV or standard FTP. Installing and configuring Time Drive requires a bit of command line work and Python, but nothing requiring any programming knowledge, and Rob explains the step-by-step of installation and use at his site.
Back in Time is a free download for Windows, Mac, and Linux systems.
Time Drive [Apolitically Incorrect]