Hello, I want to learn a framework for using php, I think wordpress is the perfect one, if there another opinion please tell me, and what is the right source to learn this framework.

Try their website. Actually, Wordpress is a CMS, not a PHP framework.

what is the difference between CMS and a framework???

CMS manages a website's content. A framework helps you programming.

Agreed with pritaeas. CMS(content management system) as the meaning of its words, help to manage the website contents even without have to know about coding. Framework is a reusable set of libraries or classes to help or speedup the development process, more like a guideline. If you wish to start developing wordpress theme, you can consider the video tutorial from thinkvitamin.com

Thank you... Ok now I want to learn a framework, I make a research and I found that Zend framework (php) is one of the most powerfull frameworks. Is it true? and what is the suitable reference to use?