FTP stands for file transfer protocol.

FTP is used to transfer files from one place to another, most commonly to transfer web pages from your local computer to your web space on the server. FTP can be done from telnet (SSH) or by using an FTP client (application) such as WS-FTP.

More information can be found here:
"How do I transfer files (FTP) using the WS-FTP client?"

(Please note that if you want to use the FrontPage Extensions to publish your webpages then you should not use FTP as it could cause errors when publishing using the extensions.)