Is IIS necessary for hosting XML Web Services ?

I am new to ASP.NET development and have a question on hosting Web Services:

When I create a XML Web Services project (server-side) in Visual Studio
2005, my Web Services file (.asmx) will be hosted by an Internet Information
Server (IIS).

I'm just wonder if I can host a Web Services without any IIS server.

For example, is there any C# classes, toolkits or services there allow me to
create a Web Services object that listens to the XML/HTTP messages directly
(i.e., not going through IIS) and send responses to the Web Services client ?

Thanks,
Peter