I need to mirror the file contents of an FTP site but the only access method is FTP (not SSH.) Currently I have an expect script that automates the download process via ncftp (which can copy whole directories automatically.) The script is rather dumb though since I have to manually terminate once all the files complete. Expect doesn't like the way ncftp displays its screens and I can never get it to properly expect the end of the file transfer. What is the best approach or even software out there that can do this and exit cleanly. I need to attach the mirroring function to a website action form that is using PHP.

Check out "rsync". Its designed for keeping directories in sync between remote hosts.

This was actually my first thought but doesn't the remote host have to be rsync enabled (acting as a server?) The only service I can use to the remote host is ftp. Can rsync function over FTP?

Go for RSYNC.
I have my own tutorial on that. I have explained some easily understandable examples over there also.
GOTO : www.amitsharma.linuxbloggers.com

And if you got any problem in implementation of that, mail me or message me or revert to this thread.

Dear i got a trick for you.

Switch off your FTP service at remote host.

In /etc/services at remote host comment out the line
#rsync 873/tcp
#rsync 873/udp.

Restart your box.

Then start rysnc at port 21 with command
rsync --port=21 --daemon

Now you are actually using port 21 i.e. FTP port for RSYNC.

On the remote side run rsync to access through port 21
rsync -avz --port=21 --progress -partial <username>@<remote-ip>::<share-name>/* /<local-location>

I TESTED THAT, IT WORKS.

For more detailed info regarding RSYNC goto www.amitsharma.linuxbloggers.com

FEEDBACK for any further query.

Unfortunately my only account access is as a limited rights FTP user. I am unable to edit the remote host's services.

FTP SYNC may help you in this.
http://freshmeat.net/projects/ftpsync/

Cheers.

This looks like a nice perl script for handling synchronization with FTP, thanks.