Rsync is a great tool to easily syncronise a folder on one server with another folder on another server.

Simply type on your command line:

rsync -r -a -v -e "ssh -l root" --delete /home/mysite/www/ 192.168.1.51:/home/mysite/www/

After entering this command, the server will ask you for a password for the root user on the second server. Enter this and your good to go.

 For a complete reference of these parameters, see: http://linux.about.com/library/cmd/blcmdl1_rsync.htm