using System;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;

[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
public class Service : System.Web.Services.WebService
{
    public Service () 
    {
    }

    [WebMethod]
    public string HelloWorld(string Name) {
        return "Hello World " + Name;
    }    
}

<webServices>
    <protocols>
        <add name="HttpGet"/>
        <add name="HttpPost"/>
    </protocols>
</webServices>

Sub CallWebService()
    Dim MSXML As New MSXML2.DOMDocument
    Dim strAnfrage As String
    strAnfrage = "http://localhost:49408/WebSite2/Service.asmx/HelloWorld?Name=Test"
    With MSXML
        .async = False
        .preserveWhiteSpace = False
        .validateOnParse = True
        .resolveExternals = False
    End With

    If MSXML.Load(strAnfrage) = True Then
        Response = MSXML.DocumentElement.Text
    Else
        Response = "Fehler"
    End If
End Sub