Simple Object Access Protocol

SOAP. Simple Object Access Protocol. A Microsoft developed distributed object protocol using XML over HTTP for the communication. It is intended for communication between systems, where a system may be a single machine or a group of machines behind a single point of contact. Fairly similar to XML-RPC.

The White Paper is located at http://msdn.microsoft.com/workshop/xml/general/SOAP_White_Paper.asp

SOAP is no longer a Microsoft-owned protocol. IBM (and Lotus, as if they're not IBM at the moment) have contributed significantly and are guiding the protocol in a more open direction.
To find out more about Simple Object Access Protocol V1.1, visit (http://www-4.ibm.com/software/developer/library/soap/soapv11.html).