Here are my posts on how to do it, Installing Ubuntu Server with all the dependencies (DynDNS client included).

SSH with Public-Key Authentication, which also enables SFTP.

I use ExpanDrive as my SFTP client on all boxes that will be accessing the server. Secure, effortless drag-n-drop file transfer over SSH from OS X and Windwoes. Nothing is easier. Yes, it is commercial software. Yes, it is worth the $40 bucks.

The last step is to ensure that port 22 is open on your firewall and you're done. I simply drag files to my home server from anywhere. It's comforting knowing they are your files in your your home, not scattered into The Cloud. I don't keep any files local on any machines, so I never have anything to sync.

Oh, and a little Shell Script to keep them backed up redundantly to two mirrored external drives.

I don't see anyone referring to these pre-installed apps by their official name... Craplets.