sms messaging without a net?

Does anyone know of a way to send SMS messages without an internet connection? Having a network monitoring system send sms pages via email very quickly runs into chicken-egg scenario. How do you email a page to let the admins know their net has gone down. :-P AT&T shut down their TAP dialup late last year. The only method that comes to mind is to buy a GSM modem which has SMS messaging capability. Has anyone done this? -Dan