PHP is an open source scripting language used to build online applications. Zend offers services and products that help developers create PHP applications, and claims that the language runs on more than 22 million websites worldwide.
Microsoft has a similar technology to PHP in its Active Server Pages product.
The two companies will propose improvements to the PHP platform that will be submitted to the community under the open source PHP licence.
Zend plans to set up a Windows testing lab to ensure performance of PHP code on the Windows platform.
Microsoft also promised to develop an add-on component to its Internet Information Services application that will interface between PHP and the IIS Web Server.
The component will be made available free of charge for Windows XP, Windows Vista, Windows Server 2003 and Windows Server 'Longhorn'.
Microsoft said that the partnership is about providing interoperability for open source applications on Windows.
"This announcement continues our commitment to making it easier for partners and developers, regardless of the development model they employ, to take advantage of increased reliability of the Microsoft Windows Server platform," said Bill Hilf, general manager of technical platform strategy at Microsoft.
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