GNU Privacy Guard: A Brief Guide

I use GNU Privacy Guard (GPG), with EnigMail (a plugin to Mozilla Thunderbird) to encrypt and sign email messages to others. I also use Windows Privacy Tray (WinPT) as a frontend to GPG. It's a good key manager, while EnigMail is more specialized to email encryption/signing/decryption.

In the past I've used Pretty Good Privacy (PGP), which is a closed-source freeware equivalent of GPG, written by Phil Zimmermann. This is also excellent software, however I prefer GPG because it isn't as dependent on other programs--no Outlook integration, a much cleaner interface (if less powerful).

Why You Should Use Encryption - an excellent guide to understanding what encryption is and why you should care.
Why do you need PGP? by Phil Zimmermann
Encryption has been used by human rights activists in foreign nations to preserve their freedom and protect the well-being of others. I'm sure one could put another slant on it, but these letters to Philip Zimmermann, the creator of Pretty Good Privacy (PGP), demonstrate at the least that encryption can be put to use for a good cause.

If you're convinced and would like to try using encryption (and are using Windows), you have many options available to you. The sites I've linked to above have fairly comprehensive installation guides. If you hit a snag though, give me an email.

One last thing to remember: you won't be able to encrypt messages unless the party you are sending to has created and made available their public key - however, you can ALWAYS sign your messages, which will at least verify that the message came from you and has not been altered. This can also generate interest in encryption in those you communicate with.