I've just upgraded a Galaxy S2 to ICS and when I now toggle data network mode by long-pressing the power button I get these time-wasting prompts like "Data network mode will be deactivated. OK/Cancel?". Any way to turn them off?
No. However, you can use an app like Widgetsoid and then create a custom widget which when pressed will toggle a number of options like brightness, WiFi, Bluetooth, 2G/3G and of course mobile data.
This will happen without any confirmation dialog popping up.