CodeIgniter

CodeIgniter is a small but powerful PHP framework. As a simple and "elegant" toolkit, it can build fully functional Web applications for PHP programmers. If you are a developer using shared hosting and struggling with client deadlines, if you are tired of those clunky frameworks

Who is CodeIgniter for?
CodeIgniter is what you need if...
You want a compact frame.
You need great performance.
You need broad compatibility with various PHP versions and configurations on standard hosts (e.g. PHP4).
You want a framework that requires almost zero configuration.
You want a framework that doesn't require using the command line.
You want a framework that doesn't have to adhere to restrictive coding rules.
You are not interested in large-scale integration libraries like PEAR.
You don't want to be forced to learn a template language (although you can choose the template parser you require).
You don't like complexity and love simplicity.
You need clear, complete documentation.