This is a handy free web-application that encrypts text using a password (the "encryption key"). We also have a handy Windows tool that does the same.
So you can send the encrypted text to your friend by email. Then tell him the password and he decrypts it back. Try it, you'll see how simple it is.
Read our FAQ for more info
This is a "just-for-fun" project by Jibit Software™, the authors of the awesome "Jitbit Helpdesk" - a saas help desk app.