protected void Page_Load(object sender, EventArgs e)
{
        //create instance for MyServiceClient class
        WCFRef.MyServiceClient obj = new WCFRef.MyServiceClient();
        //Calling service method using instance
        Response.Write(obj.HelloWorld("Ravindran"));
}

http://blogs.msdn.com/b/jmeier/archive/2007/10/15/how-to-create-a-hello-world-wcf-service-using-visual-studio.aspx