Microsoft SOAP Toolkit is most certainly a viable option to develop Web services. I recommend that you use the latest version of the toolkit. MS SOAP Toolkit supports all COM languages on all Windows platforms (Win 95, 98, NT, 2000, XP, CE). (.NET requires installation of the .NET Framework, which is only available for Win 2000, XP, and CE, it it requires that you upgrade to VB.NET and ASP.NET.) I don't view latency as a problem. MS SOAP Toolkit isn't the best performing SOAP implementation on the market, but it's certainly viable.
This was first published in October 2002