var message = new MailMessage();
message.From = new MailAddress("sender@foo.bar.com");

message.To.Add(new MailAddress("5551234567@txt.att.net"));//See carrier destinations below
//message.To.Add(new MailAddress("5551234568@txt.att.net"));

//message.CC.Add(new MailAddress("carboncopy@foo.bar.com"));
message.Subject = "This is my subject";
message.Body = "This is the content";

var client = new SmtpClient();
client.Send(message);