A quick and dirty explanation of SSL from the point of view of the SSL handshake and a quick look at Self-Signed Certificates and what they are for.
For a more basic overview of SSL check this very nice video: http://youtu.be/SJJmoDZ3il8
If you want to know more about public key cryptography see http://en.wikipedia.org/wiki/Public-key_cryptography
In the video here http://youtu.be/LHUbQtUeQ0o I show how to create a self-signed SSL certificate.
Here http://youtu.be/yjZOyANmKWU is part 1 of how to install an SSL certificate in the Apache webserver.
For more tutorials, see https://brightminded.com/updates/