It is the only PHP extension that supports a wide range of WS-* specifications. With the framework enabling the use of PHP in SOA implementations, WSO2 WSF/PHP is the ideal extension for integrating PHP legacy systems into enterprise SOA.

Federico notes some of the features of the framework including secure services/clients, binary attachments, automatic WSDL generation and interoperability with .NET and J2EE. You can find more information on the project at its page on the ws02.org site.