This plugin had been designed for cupcake device, even if it should works for newer android release.
SMS notification is not an application but only a plugin for Locale application.
It enable you to send SMS notification with cupcake android device.
See http://www.twofortyfouram.com/ for more information about Locale
Settings are very simple. You have to set a Recipent Number (number of who will receive the notification). And you have to set the SMS message.
You can prevent application to send more than one SMS by hour. Usefull if your Locale rule is fired many time...