PGP means "pretty good privacy", and is a tool for high security encryption developed by Philip R. Zimmermann. You dont have to use it, but if you'd like to maintain a sense of privacy when sending email, you can protect it with PGP. Unfortunately, if you don't already use it and would like to try, the best PGP application is a rather large download.

There is an internationally downloadable version, and those in the States and Canada can go to the site at MIT.

Frankly, I dont use this program anymore because it is such a hassle. All I need is a little program to encrypt and decrypt files and email handily. This one tries (and I am sure fails) to ensure all this happens in a secure environment by adding a heck of a lot of system-intrusive add-ons. I have yet to settle on a different program to use for encryption, so I havent bothered with PGP for a while. When I settle on one, I will put a link to it and remove the one above. In the meantime, the above software does work if you really feel the need to use PGP And can find a friend who uses it, too. That's not much of an advert, but I wont be able to get many friends to use it until there is a much more convenient program available.