An anonymous reader writes "Microsoft has caught up with the fact that open source web-based software exists, today announcing an open source project written in PHP is the first 'Certified for Windows' software that (a) follows an OSI-approved license and (b) runs via a webserver rather than operating as a native Windows executable. The software in question is SilverStripe CMS, free software released under a BSD license, that is used to build and manage websites. Certification entails a third-party performing various tests and audits on the software and giving it the green light. If other open source projects can follow suit, this will be another step in getting business folk to see that open source is ready for enterprise use. And heck, maybe even a .NET application could now seek to be certified!"