It is a pretty good idea to understand that whole public/private encryption concept before you start to think about using pgp or gpg. I remember using PGP sometime ago with DOS, but I stopped using it because it was a pain to use. To make matters worse, I think I accidentally deleted my secret key. There is an first year essay I did about PGP somewhere on the Internet. Anyway I have started using mutt, and it has great support for encryption with the GNU PGP implementation called gpg.
Generate your key pair. Default settings are fine. Use a strong password. My tip for creating passwords was told to me by another friend named Athan. Basically he says:
<li>Think of a phrase e.g. the fox jumped over the fence</li>
<li>Take the first or second letter of the phrase to make a word e.g. (with 2nd letter) houvhe</li>
<li>Throw some funny chars in there like ! and 31337(eleet or elite) transition chars like o to 0 and e to 3.</li>
With your gpg or pgp (they are the same to me) passphrase, it really needs to be strong. So, you might even want to think about repeating that process, with two phrases.
After that fun interaction, you need to export your public key and upload it to your webpage!
gpg -a --export yourusername > yourusername.pub scp yourusername.pub yourwwwhostshellmachine:public_html/
With mutt gpg is well integrated. Hit P while in the send message view for encryption options. To add public keys of your collaborators, use:
gpg --import whatevertheirpublickeyiscalled.whatevertheycalledtheextension
Feel free to send me an encrypted mail. =) My public key should be here.
The GNU Privacy Handbook is probably a better guide. :) Here is the link.