Yup, I got this message too. I was sleeping at the time and woke up briefly to hear my phone make the shutdown music instead of the recieved text message sound.
Also, I'm on sprint, and also I got the message around the same time all you folks did I'm sure.
I'm just guessing that all of you have credit unions since y'all are kinda wierded out by this? ; p
This is obviously a scam, jsut as people have been putting it ; p