My public PGP key is on the keyservers (get the one with the latest date), or you can download the key file.
Using Apple’s OS X? There’s finally a free (as in freedom), easy-to-use encryption package for the OS X Mail.app, called GPGTools.
For Windows there’s GPG4Win.
Those tools are based upon GNU Privacy Guard.
Bear in mind that if you use encrypted email, you will automatically be placed on a special targeted list by government spy agencies like the NSA and the FBI. This is an unconstitutional abuse of power. You can fight it in a number of ways. For starters, sign the petition at stopwatching.us.