If you setup SSH access to your site you can do it via command line.
Some FTP clients also have that ability. WS_FTP used to, but I haven't used it in years, FileZilla does and can.
SSH command line:
chmod 444 ost_config.php
FileZilla Directions:
Connect to the site.
Navigate the directory tree and click on the file.
Right click on the file.
Left click on Permissions.
Select the check boxes that you want.
Click Ok.
ps yes I host a site or three on GoDaddy.
