If you'd like to be able to send and receive e-mails that other people can't open, then I'd recommend having a look at Enigmail. It's an add on for the excellent Thunderbird e-mail program, which is a great free alternative to Outlook Express (or whatever Microsoft's e-mail program of choice is called this week). There are three steps. First, download and install the OpenPGP program which does all the work behind the scenes. Second, download and install Thunderbird - if you don't already use it, you should. Third, download and install Enigmail (which makes the two work together). I've written a full explanation of how it all works in an upcoming issue of Computeractive magazine.