I have iPhone 3GS not sure what network, i only have o2 and 3 sim card, i tried both but 3 sim shows no service and o2 sim does not show anything but just one bar then i tried both sims in my other sony ericsson phone but the 3 sim card seems to not work at all but o2 sim card does. Does this mean my iPhone will not work on o2 and is locked? The iPhone has also not been registered yet cos its new.