Free email web site Lockbin offers a software-free, no-sign-up method of keeping outsiders from reading your messages. The process is fairly simple—after clicking through an agreement and CAPTCHA page, you write your message and choose a secret word. After you tell the recipient the de-coding word (hopefully any way but email), they can read the message once on Lockbin's site before it's deleted forever. As the site itself notes, it's not perfect encryption, but it's a pretty easy way to keep email snoopers away from your message. One footnote: Two test emails I sent yesterday were delayed for more than four hours, but another message went through instantly this morning. If speed is a necessity, try encrypting your own email or using Greasemonkey to encrypt Gmail.