Ok I'm not 100% sure what you are after.
From the sounds of it you want to set up a local server to start writing PHP code to build websites, correct?
If so download a program called WAMP, assuming you are on a windows machine.
Install PHP 5 Apache MySQL on Windows : WampServer
There are also others such as xamp etc.. different people have different preferences, but WAMP has been good for me.
You can use dreamweaver as your text editor with no issues. It reads and displays PHP files nicely.
So once you have wamp running all you need to do is navigate to
http://localhost/ to view your pages etc..
May I ask what you are trying to achieve though? Delving into PHP could be very time consuming. If you are a front end designer it might be worth spending time learning how to theme an existing open source CMS such as Wordpress / Joomla / Drupal. Wordpress being the easiest to theme of the bunch.
You don't really need to know lots of PHP code to build a website. In fact its possible to build a dynamic site without knowing any php.
If you are looking to learn php code and want to code may I suggest you learn to build websites using a framework such as code ignitor?
CodeIgniter - Open source PHP web application framework
Hope that helps.