As a part of his work for the WinPHP Challenge Juozas Kaziukenas looks at some of the external library types that you can use with your (Windows) PHP applications.

External libraries are useful for performance demanding tasks where PHP is simply too slow. Also PHP can work as front-end system for various back-end systems (where server doesn't provide any PHP supported communication types). I have written some posts about using .Net libraries in PHP so far, but there are some other choices available too.

He looks at the three types of library choices - PHP extensions, exec call. For what he wants to do, though, the COM objects are the best fit for the job.