Niftytelnet ssh is a Mac application that allows Mac users to connect using secure shell (ssh), which is a secure replacement for telnet. Niftytelnet ssh also has an scp (secure copy) facility that serves as a replacement for ftp.
Here is a copy of niftytelnet.
More information on niftytelnet ssh can be found at http://www.lysator.liu.se/~jonasw/freeware/niftyssh/
Here are several pages showing step by step instructions for setting up niftytelnet for both ssh connections (i.e., remote logins) and for scp (i.e., file transfers).