Yes, .NET will run on Windows NT 4.0. To run the .NET framework, you will need Microsoft Windows NT 4 (Workstation or Server) with Service Pack 6a. There are advantages to upgrading to Win2k, however, and I would urge you to consider this option. Win2k has security advantages over NT; it has reliability and scalability advantages with COM+ and IIS 5.0, etc. Windows.NET is just around the corner, making NT 2 generations behind as a server OS. If you are using NT workstation, it is already behind both Win2K and XP.
Calling SOAP from ASP 3.0 or earlier - the easiest way, I believe - is to use the SoapClient object available in the MS SOAP toolkit. The toolkit can be downloaded here.
The client has 2 APIs: one is a high level API the other is a Low Level API. You can probably use the high level API which simplifies coding, assuming you have a WSDL for the Web service available. Keep in mind that when calling the MSSoapInit method from an ASP page or another multithreaded environment, you must set the ServerHTTPRequest property (using the ClientProperty property) before calling that method.
This was first published in August 2002