Creating custom posts types is a great way to customize your WordPress website and expand the database functions. You can create custom post type easily by using a plugin. Or you can build the functionality in with code. I have listed some handy resources available for custom post types that I have found useful.
Randy Jensen has a great video about building custom post types. He has developed a set of icons for custom post types that you can also download from this post. http://randyjensenonline.com/thoughts/wordpress-custom-post-type-fugue-icons/
Here is a good article about how to add custom post type icons by Devin at WP Theming. http://wptheming.com/2010/11/how-to-use-custom-post-type-icons/
This site is called Custom Post Type Generator. It is amazing. You fill out some fields and the code snippets you need are automatically generated for you.
This is the codex insertion about Custom Post Types. http://codex.wordpress.org/Post_Types