On my BlackBerry, the phone would start just to sound the alarm, does the same happen for the iPhone?
No, the iPhone does not have an auto on/off feature that bb has so that you can set that, and then in turn set an alarm to sound 5 mins after turning on. If the iPhone is off, the alarm will not sound.
On the other hand, if your iPhone is on, but you have the side switch set to vibe all, the alarm will still sound as it normally should. I do this every night so that my incoming texts or emails don't wake me, but my alarm will.
Ah ok, thanks all, but thanks Pink, I'll just do that, though I'll probably disable vibration so it doesn't vibrate off my bedside cabinet and smash in to pieces.