Actually, using Terminal for FTP is not that tough. And you don't need to install any software, it is all there already.
To establish an FTP session to the site in question, just issue this command:
ftp site-name
You may be prompted for a username/password, just like any other FTP client.
To upload a file, just issue this command:
put name-of-the-file-on-your-mac
To download a file, just issue this command:
get name-of-the-file-on-the-ftp-server
Thats it. It is really easy. The only issue you may run into (and you run into this on ALL ftp clients by the way) is the infamous Passive mode, which I freely admit I don't understand.
To test if things are set up right, after you have connected to your site, issue this command:
ls
This lists the contents of the site. If nothing happens, you have fallen victim to incompatible passive settings. Kill this session (CTL-C usually does it, or just kill the Terminal window entirely) and start again. This time, after you are logged in, issue one of the following commands. They all do the same thing, but the command name varies from FTP server to FTP server. So, one of:
epsv
passive
pasv
Try "ls" again. When you are getting a directory listing back, you have sucessfully switched to a compatible passive mode. Now carry on.
Easy, easy easy. Try it, you'll like it. There is a WORLD of power hidden in the much ignored Terminal command set. If you take any time to investigate, you will be amazed at what you can do there.