rsync can do this and can also automatically append a timestamp to your backup files.
You can also put a rsync command straight into cron. As an example for a daily backup:

@daily rsync -ab --suffix=_`date +%F` -R {server}:/var/wwww /home/backups/

(this assumes you can already access this machine and that /home/backups/ exists and you also need to change {server} to the system where the files are)

The links posted in comments uses this as an example but has a better method end result: a backup script that you use from cron.