For secure email, I've been using a form processor called SouperMail, which can interface directly with the Gnu Privacy Guard installed on TCH servers and encrypt messages with your PGP key before sending them. I'm not sure about the PC side, but for macs, I've been using the personal version of PGP, which interfaces directly with the mail program, and only decrypts the message for the current session - quit the program and come back, and it's still encrypted. You could also just use Gnu Privacy Guard to decrypt the messages - it has GUIs for both Mac and Windows (and Linux, of course), and upon decryption displays the plaintext in a separate window, leaving the original message in its encrypted form.