WSDL and UDDI

Services discovery and description

So how do people find out about these services? Google can't exactly index Web Services, since they rarely host a traditional textual page. Ordinary Web directories aren't exactly designed for automatic searches leading to API definitions...
Web Services Description Language WSDL is the part most developers find easiest to grasp, providing a machine-readable description of APIs exposed by particular services. WSDL uses XML and W3C XML Schemas to define the contracts supported by Web Services.
Universal Discovery, Description, and Integration UDDI provides a searchable set of services, offering equivalents to telephone white pages and yellow pages, as well as more technical "green pages". Originally conceived of as a centralized repository for the world's services, it has largely decentralized as organizations want to control their own lists of approved services.
Intellectual property IBM and Microsoft both have patent claims on WSDL, and UDDI is managed by a much more closed consortium than the W3C. Both are still in relatively early phases of development.