What is your previous programming experience? If it is also Object Oriented Programming with C++, Java, C# or Action Script, then you can easily learn PHP.
PHP has now evolved from an event/logic driven programming language to a powerful Object Oriented Programming. The latest version is PHP6 which is designed for OOP and a lot more powerful features.
If you have mastered Object Oriented Programming (OOP) with PHP then you can move on to studying Design Patterns in PHP.
There a lot of tutorials available that you can download in the internet. I would recommend the following video tutorials:
1. Nettuts.com - Object Oriented Programming with PHP by Jeffrey Way
(Jeffrey Way is the Manager of the biggest Wordpress Marketplace - Themeforrest.net)
This is a beginners level tutorial of OOP with PHP.
2. KillerPHP.com- Beginners PHP
3. KillerPHP.com- Advanced PHP
4. Lynda.com- Dreamweaver CS5 with PHP and MySQL
For code editors, there are a lot of powerful FREE code editors and IDE's for PHP. But most of these free editors are Java based which would require you to Install JRE and the Java SDK. And also Java based editors are quite slower compared to other IDE's which is created in C++ or Visual Studio:
1. Eclipse - PDT Plugin (Available at Eclipse.org) - FREE
2. Netbeans PHP - FREE
3. Aptana Studio 3 - FREE
4. Adobe Dreamweaver CS5.5 - Not Free but with 30day Free Trial.
(If you are learning PHP at a beginner level, I would recommend you use Dreamweaver for it is a very powerful IDE with a lot of features to assist you like Code Hinting, Site Management, Related files viewing, a WYSIWYG editor,Syntax Checking and Debugging features. )