Been playing around with a new open source toy I found http://www.djigzo.com/.
Basically it takes email you send to it and creates a 128-bit AES encrypted PDF of the email message and all attachments.
This project is simply amazing and rivals some several thousand dollar devices I've seen.
Basically you can encrypt all email or have it encrypt based on a keyword in the subject.
This claims to work with any mail server as it just uses postfix MTA and you just forward all email from your existing MTA to it.
Really is a neat project just wanted to share. Plus they have a virtual appliance for vmware to make tinkering really easy.