You need a SMS-Provider to send SMS for alerting.
In our case we send an eMail with the alert to our SMS-Provider and they send us a SMS with this alert.
For alerting yourself by SMS you need to fill the "Phone"-Number and the "SMS Address" in the Users Details. The "SMS Address" is the eMail-Adress of your SMS-Provider (in our case it's smssend@sms-gate.net).
Than we modified the eMail-Template in the form that our SMS-Provider need it to interpret the eMail. You find the eMail-Template in the server-folder under "hq-engine/server/default/deploy/hq.ear/alertTemplates". The file to modify is "sms_email.gsp".
Your SMS-Provider will tell you how the eMail has to be formed. In our case it's an XML-Format:
<?xml version="1.0" encoding ="UTF-8"?>
<smssend>
<userdata>
<uid>smsgate_username</uid>
<pwd>my_secret_passphrase</pwd>
</userdata>
<messages>
<message>
<src>my_server</src>
<dst>${user.phoneNumber}</dst>
<userdata>${action.shortReason}, ${action.longReason}<%
if (alertDef.description) { %>, ${alertDef.description} <% } %></userdata>
</message>
</messages>
</smssend>