WS_FTP is a very good ftp client, but.....
FTP is bad because it sends your password in cleartext (i.e. a snooper or eavesdropper could read it) accross the network. (The file can also be snooped of the network).
If you can - try to use Secure FTP or SCP. I sometimes use a program called winscp to do this - which is free and also has a nice UI, and - did I mention? It's free. Of course, it depends on weather the people you're trying to ftp to will allow you to use a different access mechanism.
Of course - you'd probably be okay 99.9% of the time...YMMV ... I work at a Security company - so I have to think about it all day every day