Encrypt Email sends email messages with encrypt attachments.
Mac based recipients will receive a DMG password protected file.
Windows and Linux based recipients will receive a ZIP password protected archive.
You can send these messages with your usual email client (supported clients are Apple Mail, Entourage and Eudora, if your default client email is another one, will be used Mail), or directly with Encrypt Email after entering a valid account. Please note that some email providers don’t accetp encrypted ZIP files attachments. One of such providers could be Gmail, please read a post on this topic on Google forums.