Best SCADA remote acknowledgement

What has been your experience with remote Alarm acknowledgement by Wastewater operations personnel for example. Message to pager, call in Telephony acknowledgement is the norm I suppose. What else is there, that you have DIRECT experience with?

I'm thinking SMS to blackberry or cellphone and replying with ack code to acknowledge alarms. Has anyone done this? I'm using ICONICS software that supports lots of these things, but I'm interested to hear what other approaches have been taken.