Install a local webserver (WAMP/XAMPP). You can use a text editor, but a good IDE to help you write code and debug is recommended. Use php.net as your main reference, decide on an application to build, then find a tutorial on that specific subject to get you started.
I personally don't sugest you use an IDE like Netbeans or Dreamweaver, they sometimes can create junk code, and they style your code. I believe everyone should have there own style and understand everything they are writing. So I reccomend Notepad++ it's absolutely perfect. For a project, probably something with a form and database insertion? Then pulling it out? Just keep practicing to, give you so much more understanding. Also Google and php.net are your best friends!!
The best way to learn is to go through php manual site http://php.net/manual/en/
It starts with basic php syntax and defines all the functions available in php and its latest happenings.
As for IDE is concerned,you can install WAMP server and then use Notepad++ ,lightweight and easy to use.Select just the language in Notepad++ and you are ready to see the syntax of the corresponding language in Notepad++.
w3schools has been error-ridden in the past, so be careful if you use this as a resource.
A number of IDEs free and otherwise are more than capable of meeting your needs. Dreamweaver is very expensive, but it doesn't have to produce nonsense code if you write it all yourself. However if you're starting out, as it seems you are, then have a look at a few editors / IDEs and use the one you find easiest to use. Here are a few that haven't been mentioned yet:
You'll also want to start dabbling with MySQL pretty quickly after starting php, so I suggest getting a nice GUI as phpMyAdmin, although very good, can be a bit clunky. My favourite is SQLyog community version: https://code.google.com/p/sqlyog/downloads/list