FTPLab.Com  
   How to choose an FTP program. About tasks which can be performed by a special program called FTP Clients.
   http://ftplab.com/

FTP Protocol Overview  
   Very brief (1 page) overview of FTP. Part of "Connected: An Internet Encyclopedia"
   http://www.freesoft.org/CIE/Topics/69.htm

FTP File Transfer Protocol  
   Lecture slides providing an overview of FTP by "Dave H".
   http://www.cs.rpi.edu/courses/fall96/netprog/lectures/html/ftp/

The Internet and FTP  
   One of the most useful services of the Internet is FTP, or File Transfer Protocol. This paper describes the client/server environment and explains FTP conventions and issues.
   http://www.islandnet.com/~tmc/html/articles/ftp.htm

FTPmail: FTP by email  
   FAQ describing how to download from ftp sites with email.
   http://www.faqs.org/faqs/internet-services/access-via-email/

FTP: File Transfer Protocol  
   Reference manual aiming to describe how FTP actually works (and doesn't work) in practice.
   http://cr.yp.to/ftp.html