Secure GnuPG Form is a Web form that sends encrypted email and attachments using GnuPG, without the sender needing to have GnuPG installed. Versions are available with Recaptcha.net support and two-factor authentication using a username and password and the free PhoneFactor.com service.
tkpg is a program that provides a GUI front end to Philip Zimmermann's Pretty Good Privacy (PGP) public-key encryption system and also the GNU Privacy Guard (GnuPG/gpg) implementation. It utilizes the Clipboard Selection heavily to ease moving pgp-processed text both to and from any of your applications (such as mail reader, news reader, and editor). This removes the need to select the output text by hand or by typing in a filename, since it is usually placed in the Selection automatically for you.