With the Code below I get the following output in the serial monitor. Notice how it doest print the full message in the serial monitor (missing " Hi!") and more importantly this code does not send anything via sms. If anyone knows why this is please help me, thank you 
Setting AT commands to text mode...
Trying to send to number...
Writing message...
Message should be sent!AT+CMGF=1
AT+CMGS="+61xxxxxxxxx"
SIM900 and Arduino say
void setup()
{
Serial1.begin(19200); //Default serial port setting for the GPRS modem is 19200bps
Serial.begin(19200); // the GPRS baud rate
delay(500);
}
void loop()
{
//after start up the program, you can using terminal to connect the serial of gprs shield,
//if you input 't' in the terminal, the program will execute SendTextMessage(), it will show how to send a sms message,
if (Serial.available())
switch(Serial.read())
{
case 't':
SendTextMessage();
break;
}
if (Serial1.available())
Serial.write(Serial1.read());
}
void SendTextMessage()
{
Serial1.println("\r");
delay(1000); //Wait for a second while the modem sends an "OK"
Serial.println("Setting AT commands to text mode...");
Serial1.println("AT+CMGF=1\r"); //Because we want to send the SMS in text mode
delay(1000);
//Serial1.print("AT+CSCA=\"+61xxxxxxxxx\"\r\n"); //Setting for the SMS Message center number,
//delay(1000); //uncomment only if requiredh
Serial.println("Trying to send to number...");
Serial1.println("AT+CMGS=\"+61xxxxxxxxx\"\r"); //Start accepting the text for the message
//to be sent to the number specified.
//Replace this number with the target mobile number.
delay(1000);
Serial.println("Writing message...");
Serial1.print("SIM900 and Arduino say Hi!\r"); //The text for the message
delay(1000);
//Serial.print(26,BYTE); //Equivalent to sending Ctrl+Z
Serial1.write(26);
//Serial1.println((char)26);
Serial.println("Message should be sent!");
Serial1.println();
}
