Jetico BCTextEncoder - Jetico BCTextEncoder is software that ensures your text-based communications are safe by allowing you to encrypt them.
Toolsley PGPigeon - Simple but powerful OpenPGP-compatible message encryption webapp.
TheLetterEncrypter - TheLetterEncrypter is a small (14KB download) AES-based text-encryption program.
GPGTools - Use GPG Suite to encrypt, decrypt, sign and verify files or messages.
GNUPGK - A GnuPG Frontend GUI made in C#.
Lockbin - Lockbin is a web application for sending private email messages and files.