Most email clients can be configured for securing connections by using authentication and encrypted connections.
NOTE - Exchange (Connect) Email account connections are secure - no additional configuration is necessary.
Most mail servers on campus require you to authenticate in order to send mail.
An encrypted connection between the email server and your computer ensures secure transmission of your userid, password and your message text.
The preferred protocol is TLS (Transport Layer Security) when available, rather than SSL (Secure Sockets Layer).
Configuration for some popular email clients:
Outlook Express 6
Outlook 2007
Outlook 2002
Eudora 6.x for Windows
Eudora for Mac OS X
Mozilla Thunderbird V1.0+
Mozilla Thunderbird V2.0+
Macintosh Mail for 10.2 to 10.4
Macintosh Mail for 10.5 (Leopard)
Macintosh Mail 10.5 for Exchange
Microsoft Windows Mail v6.0
Microsoft Entourage 2004