Officials at the two companies explained that much PHP development is occurring on Windows desktops systems, but the applications themselves are then being deployed on Unix boxes because of limitations with Windows Server. Tuesday's announcement aims to cure these performance issues. PHP has become a popular scripting language for Web development.

"We will be leveraging Windows-specific APIs to make the best possible performance on Windows," said Andi Gutmans, co-founder and chief technology officer at Zend.

"The way PHP's run on Windows up to today is in a way that does not perform," Gutmans said.

The vendors will announce their multifaceted collaboration at the in San Jose, Calif. Key to the arrangement is an interface between PHP and Microsoft's IIS (Internet Information Services) Web server. Called FastCGI (Common Gateway Interface), the interface will be free for users of Windows Server 2003 and the upcoming Windows Server "Longhorn."

"We're building a piece of technology called FastCGI, that will help [significantly] the performance of PHP in the Windows Web server environment," said Bill Hilf, Microsoft general manager for technical platform strategy.