Best FREE PHP IDE
1. Netbeans - Download
2. Komodo Edit - Download
3. Notepad++ - Download
They all have code completion, Syntax highlighter and Lot more . And also supports PLUGINS .
Netbeans is the best if its a bigger projects and requires a Bit extra memory among the three .
Komodo Edit is good for faster Coding and also requires Low Memory.
Notepad++ is a lightweight and it supports almost all programming lanuguages.
Some Commercial IDE For PHP are
1. Zend Studio
2. Dreamweaver
3. Komodo IDE