Bulk sms to a smart group in civi 4.4?
You don't say what version of CiviCRM you are on.

I am sure you can do this with scheduled reminders in 4.6 or 4.7 provided you have an SMS gateway configured. See http://docs.civicrm.org/user/en/stable/sms-text-messaging/set-up/  and http://docs.civicrm.org/user/en/stable/email/scheduled-reminders/

You won't need a smart group as once you have selected the event you can specify which participant statuses are sent the SMS.