Using PGP keys is a way of encoding a message.
The basics: there are two keys for every individual, a public key and a private key. You send people your public key, so that they may encrypt documents, email, etc. with your public key, and send it to you. Then, you use your private key to decrypt the file.
The wp2pgpmail plugin makes this process seamless: you enter your public PGP key once you install the plugin. After that, the key will be used to encrypt the data filled by your visitors from the form.
So, it’s a simple and efficient solution, without the need of SSL.
