I just got an email from Ubisoft regarding the demo and it had the above at the bottom of the email. I already texted and got my code. Just in case there's anyone here that can't see the image here's the message:
"TEXT WEAPON TO 44144 FOR A FREE, EXCLUSIVE IN-GAME WEAPON FOR SPLINTER CELL CONVICTION ON XBOX 360. HURRY! LIMITED NUMBER OF UNLOCK KEYS AVAILABLE!"
Edited by LinkinPrime, 18 March 2010 - 06:39 PM.