--Open this script in a new Script Editor window.

on adding folder items to myLocalDropbox
    -- Convert the path of the local folder to one rsync can understand
    set myLocalFolder to the POSIX path of myLocalDropbox
    -- Set our remote user name and the server we're syncing to
    -- Keep the name and servername in quotes
    set myRemoteUser to "your user name"
    set myRemoteServer to "your server"
    -- If you want to sync with a different folder, change "Dropbox" to the folder you want to use.
    -- Remember to keep the name in quotes.
    set myRemoteFolder to "Dropbox"
    -- set a variable to make the command more readable by combining our remote user, server and folder:
    set myRemote to myRemoteUser & "@" & myRemoteServer & ":" & myRemoteFolder & "/"
    do shell script "rsync -avz " & myLocalFolder & " " & myRemote
end adding folder items to