I think I posted this once before, but it's worth reposting. Many modern email clients include hooks for encryption/digital signatures that can go a long way to secure the email system writ large. I use OS X; its default client, Mail.app, includes support for S/MIME.
Anyway this posting is a public service and a call to action. Secure your email! Pay a visit to Thawte and get a free identity certificate, then plug it in to your email client. OS X users can use these great instructions. The rest of you, try Google.