You may use U.C.ME-OPC alarm notification software. It is easy to use and offers good functionality. It uses OPC (or DDE) to connect to any OPC server or SCADA/HMI software that supports OPC or DDE server functionality.
Alerts may be sent via: Email, SMS, Phone(Voice), Fax, Multimedia and WAP. It may also be used to analyze your alarms and understand the root cause of the alarms.
You may also send SMS commands from your cell phone to U.C.ME-OPC to change or query tag values(analog/digital).
See www.controlsee.com . A fully functional evaluation version can be downloaded.