It's in the documentation:

http://www.concrete5.org/documentation/developers/blocks/creating-a...

Good luck!

Is there a book for programming in Concrete5? One of the things I hate with most CMS, is that they are built on a framework (Zend in this instance) but, to code in the CMS....I have to learn an entirely new framework. My take on concrete5, is that it is the case.

Unfortunately there is no book (yet -- care to write one once you've figured it out?)

And just so you're not confused, concrete5 uses some Zend Framework libraries, but it is not really built on the Zend Framework in the sense of being structured a certain way.

I think every CMS is going to require learning how it works -- every CMS is really its own framework -- that's kind of the point (that they work differently than other systems -- hopefully better, at least in the eyes of the CMS developer).

So what's the best way to learning how to code in concrete5? For 2 years, I've been fiddling around CMSs to find something that allows me the flexibility to code. Joomla...was a horrible experience.....complex library and syntax really sucks. And oh...yeah I would love to write a book on concrete5 for other enthusiast of the framework but, not sure how the core developers would feel about that.

Start with the link that Benji provided above. It's also really helpful to look at the code of the built-in blocks that come with Concrete5 (in the concrete/blocks directory).
And the core developers would be *very* happy if someone wrote a book about concrete5 -- anything that makes it easier for people to use it and expand the community is a benefit to everyone.