Transmit is an excellent FTP client, and hands down my favorite for the Mac. One of its niftier features is that of opening up a file on the remote server in a local editor, and uploading the changes automatically as they are saved in the editor.
This didn't work out of the box in emacs, but I found a fix (h/t to Justillilly.com).
In your user directory, you'll find a hidden file called ".emacs" Edit the file to add the following:
(setq backup-by-copying t)
Or, you can use the in-emacs preferences. If you type M-x (refer to the tutorial if you're not sure what that means), and then "customize", you'll get to a customization screen. Select "Files", then "Backup," and toggle "Backup By Copying" on, and save the results. This will automatically add the entry to your '.emacs' file.