Ok,
So I found a 12V 7Amp power supply that I have plugged into my Arduino Mega. I believe this should work as the iComSat has it's own voltage regulator that gets power from the Vin pin on the Arduino board. Using the code that tbarat posted, and using pins 6,7 as my RX1,TX1, I was able to communicate with the SIM900. I could send it the AT command with an "OK" response. I checked that the SMS message center number is set correctly, and also checked the band frequency (+CBAND: GSM850_MODE,ALL_BAND). I assume this is correct, doing a bit of research I found that my carrier operates on GSM850/1900. I was able to call my iComSat and saw the "RING" on the terminal display.
Anyways I still have a problem. When I try to send a text message with the CMGS="+15554445555" it responds with the '>' sign meaning it is ready for me to type text; however when I finish typing and hit enter the terminal program shows another '>' sign....
I wait, and wait but the text message never comes.
Any ideas of what I might be missing here?