When I first bought the iphone, I was extremely wary of its
ability to stay connected to the internet, even in GSM 900/1800
mode. During that time, there was still no cap, and 12gb data plan
is unheard of, which makes me all the more wary.
I then learnt how to disable the always on connection by
altering the APN thru the cellular data network option, but its
quite a troublesome process when you need to use the internet.
Then when the other 2 telcos entered, the min data plan bundled
was 12gb, and believe me, it is alot alot alot. Because if you
could still exceed that, your phone is most probably permanently
power plugged to the wall. Now I don't mind setting it to permanent
3G connection at the expense of battery life.
The only possible way for the data charges to accumulate so
tremendously is the use of the maps app in addition to the location
services being switched on. But by doing so, the phone will
discharge battery power at an extreme rate, the battery might not
catch fire, but it'll be too hot even to hold on. I have personally
tested it to that extreme. So drivers, please note the iphone is
not a good gps device.