OpenPGP is a standard for encrypted e-mail messages. Wikipedia article on PGP. I use the GNU Privacy Guard. You might want to do the same.
My current OpenPGP key is 1024D/E4C92FA5 2005-10-26 with the fingerprint:
673B 563E 3C78 1BA0 6525 2344 B22E 2C10 E4C9 2FA5
The key is also available on many key servers, specifically the NIC-SE PGP key server or any of the keyserver in the pgp.net. It is also available on PGP Corporation's PGP Global Directory.
My former key, 1024D/6D6F99DF, has been revoked. Don't use it, unless you need to verify very old messages.