Just downloaded and tried this and it doesn't work. I recieve emails from my site and I can send an email direct to my t-mobile usa account and i get the txt message. When using this, it doesn't work.
A very cool idea but need to be able to have subscribers subcripbe to groups or WP post categories so we don't have to sms everyone! (maybe this is in here but since I can't get the subscribe txt msg, I can't test)