I suggest you use what comes with OSX, namely sftp/scp, included with every OSX since the age of dawn.
Enable SSH in the sharing (Remote Login), configure what users have access and then try to use sftp from the Terminal (if you are familiar with it). Try
man sftp
to see the help.
DESCRIPTION
sftp is an interactive file transfer program, similar to ftp(1), which
performs all operations over an encrypted ssh(1) transport.
You have the benefits of "ftp-like" plus everything is encrypted.
If you still want to go ahead and use ftp, I suggest you take a look at ftpd conf file, located in /etc/ftpd.conf and /etc/ftpusers
In any case, take a look at the man page for ftpd.conf and ftpusers:
man ftpd.conf
man ftpusers
…to see other options you can add there (because the default one will be most likely empty or with little things in it).
There's no pretty program to configure FTP on OSX (there is on the Server version as far as I can remember).
Please note that FTP is not a very secure protocol by default and hence it should be running inside a chroot. (hint: man ftpchroot).
On a Mac I've actually had some trouble with FileZilla as Chris mentioned.
I personally prefer Cyberduck (http://cyberduck.ch/) which has worked very well for me. Especially in cases where Finder could not handle things like:
ftp://siteaddress|user@logindomain
Best Answer
You may want to try a dedicated FTP application, they tend to do a better job (in my experience) than using Finder for FTP copy. Also if you are comfortable in the command line you can do FTP there as well.