Some FTP clients, such as
http://www.smartftp.com/ , support FXP, which supposedly lets you FTP server-to-server. WS_FTP Pro (
http://www.ipswitch.com/ ) looks like it has this feature too. The servers would have to support this. I've never tried it myself. I was at the point of investigating it once, but then I remembered that since I had telnet access to one of the servers, I didn't need it.
Another option (if you know Perl) is to write a Perl script which uses the Net::FTP module to do the transfer.
[ 11-17-2001: Message edited by: Dave_L ]