I really want to know how i can broadcast(live) in my web page

what kind of control to use nd .....just how to do it....

really..!!!!!!!

you can define a global variable (Application) in Global.asax file like this

Application_Start(...)
{
Application.Add("message", "");
}

when you want to send a message, you should set your message into Application["message"] property like this

sendButton_Click(...)
{
Application["message"] = messageTextBox.Text;
}

and in your pages in Load event (Page_Load(...)) check that if message is not empty, you should show it. and if you want you can a Ajax timer to check this in some periods of time.