How To encrypt a message with password protection?

I'm sure it's easy, but I'm not sure where to start looking for the tool. I want to be able to encrypt a message and protect it with a password. Say, for example, I had some one monitoring my mail traffic and spiking certain messages. If I could encypt the message in such away that it could be unencrypted using a passoword this would be an ideal way of prevent the censor form spiking my traffic. After the fact, I don't care who can read the message. I need something that will work easily for all common platforms. I may try X509 type solutions, but they don't really serve my purpose. It's important that this tool is easy for anybody to obtain and use. Any ideas? Steve PS run kdict, and query on *censor*. #1 & #2