WWSAPI is a native-code implementation of SOAP Web Services for both Windows client and server endpoints. WWSAPI provides core network communication and distributed computing functionality by supporting a sub-set of the WS-* protocols. A designer might choose to implement solutions using WWSAPI given the following requirements, for example:
Until now, the WWSAPI runtime library (i.e. "WebServices.dll") has only been available on beta Windows 7 (the client) and Windows Server 2008 R2 (the server). Developing for either client or server endpoints required the pre-release Windows 7 SDK to access the "WebServices.h" header file.
Now, WWSAPI has been back-ported to include support for XP, Server 2003, Vista, and Server 2008. WWSAPI is still not officially released and is made available as a beta version only.
You can obtain the build and runtime components of WWSAPI at the Microsoft Connect website: http://connect.microsoft.com/WNDP/content/content.aspx?ContentID=11205
Learn more about WWSAPI via Nikola Dudar's blog or via MSDN Code Gallery.