The code below demonstrates a quick way to email all the exceptions that occur in an application:
protected void Application_Error(Object sender, EventArgs e)
{
Exception ex = Server.GetLastError();
MailMessage msgMail = new MailMessage();
msgMail.From = "autoadmin@sms.com";
msgMail.To = "admin@sms.com";
msgMail.Subject = ex.Message.ToString ();
msgMail.Body = ex.ToString ();
msgMail.BodyFormat = MailFormat.Html;
SmtpmsgMail.SmtpServer = "localhost";
SmtpmsgMail.Send( mail );
}