Using rsync is great way of keep remote files up to date, like having a fresh backup somewhere. I use it on most of my webservers so that I always have a remote copy if a server would crash. When setting up a cronjob you need to either install a key on remote server or send a public key to avoid a password question.
ssh-copy-id is a script that uses ssh to log into a remote machine and install your public key. I recently had to do this on a server that had ssh on a different port. Normally as you do “-p 6000″ but in this case a bit tricky