In a new post to the JSLabs blog, Justin Silverton talks about a method - using the Roadsend Compiler to convert PHP scripts into Windows DLL files.

I came across this great open source project that allows you to convert your php scripts to a fast/cgi executable that can be executed by any web server that supports it (including apache and IIS).

Roadsend is a native compiler for PHP that converts scripts into free-standing binaries and can be used for building both online and offline applications.