WordPress will be a difficult blogging platform if not for the plugins that alter the look and feel of your website. Almost any tweak can be done using a WordPress plugin from a simple tweak to an overall makeover. Plugins can change how your WordPress blog works.
In this article, we’ll show you how to create your very first WordPress plugin. We’ll start with how to structure your plugins, providing a naming convention for it, cleaning up the code, and documenting and using proper coding standards. We’ll also test and prepare your plugins before we’ll be able to use it.
Read the rest of the tutorial here: http://wp.smashingmagazine.com/2011/09/30/how-to-create-a-wordpress-plugin/