Kludged together a quickstart guide to email through telnet from this story on slashdot.org
(From comments by xQx, carm$y$)
telnet [your mail server] [port – usually 110 for POP3]
USER [username]
PASS [password]
Once you’re in:
STAT gives you number of messages and total size
LIST gives you a list of your messages
RETR [message number] to read a message
HEAD [message number] [bytes] (I couldn’t get this to work on BT’s mailserver but I assume it gives you the first part of a message)
DELE [message number] deletes the message permanently
And when you’re done:
QUIT
You can also send email via telnet