Notes:
Applications: service description, registration and discovery, execution.
WSDL is Web Services Description Language. XML format for describing network services. Works with SOAP, HTTP and MIME (email).
http://www.w3.org/TR/wsdl
DISCO is Discovery of Web Services. Way to discover and retrieve WSDL description of services on remote machines. Using the Discovery Document Format (also an XML grammar), can send a discovery document to a remote server and, if any SOAP enabled services (AKA web service) exist, receive back an WSDL description of the services provided. Crops up in .NET quite a bit.
UDDI is Universal Description, Discovery and Integration. Industry initiative to enable businesses to quickly, easily, and dynamically find and transact with one another. UDDI enables a business to (i) describe its business and its services, (ii) discover other businesses that offer desired services, and (iii) integrate with these other businesses.
http://www.uddi.org/
XML-RPC is remote procedure calling using HTTP as the transport and XML as the encoding.
http://www.xmlrpc.com/
SOAP is Simple Object Access Protocol. Lightweight protocol for exchange of information in a decentralized, distributed environment.
http://www.w3.org/TR/SOAP/
ebXML is electronic Business using eXtensible Markup Language. Standard method to exchange business messages, conduct trading relationships, communicate data in common terms and define and register business processes.
http://www.ebxml.org/